Partially typed semantic based query execution optimization

ABSTRACT

A method includes receiving an initial pipeline including a sequence of commands for execution on a computing system, and obtaining, for each command in the sequence of commands, semantic information. The sequence of commands includes a command with incomplete semantic information. The method further includes generating an abstract semantic tree (AST) with the semantic information and a placeholder for the incomplete semantic information, and manipulating the AST to generate a revised AST. The revised AST corresponds to a revised pipeline that reduces an execution time on the computing system. The method further includes executing the revised pipeline.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 16/669,429, filed Oct. 30, 2019. U.S. patent application Ser. No. 16/669,429 is a continuation of U.S. patent application Ser. No. 15/582,519, filed Apr. 28, 2017. Accordingly, this application claims benefit under 35 U.S.C. § 120 to U.S. patent application Ser. No. 16/669,429 and U.S. patent application Ser. No. 15/582,519, which are incorporated herein by reference in its entirety.

BACKGROUND

During operation, computer systems execute instructions. Because of the volume of instructions used to complete a task and to hide the operational complexity of the computer system, abstraction is used. In other words, the abstraction hides the complexity while simultaneously allowing various developers and users to create instructions and commands that are performed on the computer system. Multiple levels of abstraction may be used. Each level increasingly hides the instructional complexity of the computer system performing the requested operations. For example, end users that interface with applications at the highest level of abstraction may not even contemplate how the end user's commands to the applications are being executed, much less be able to change the commands to efficiently execute.

BRIEF DESCRIPTION OF DRAWINGS

In the drawings:

FIG. 1 illustrates a networked computer environment in which an embodiment may be implemented;

FIG. 2 illustrates a block diagram of an example data intake and query system in which an embodiment may be implemented;

FIG. 3 is a flow diagram that illustrates how indexers process, index, and store data received from forwarders in accordance with the disclosed embodiments;

FIG. 4 is a flow diagram that illustrates how a search head and indexers perform a search query in accordance with the disclosed embodiments;

FIG. 5 illustrates a scenario where a common customer ID is found among log data received from three disparate sources in accordance with the disclosed embodiments;

FIG. 6A illustrates a search screen in accordance with the disclosed embodiments;

FIG. 6B illustrates a data summary dialog that enables a user to select various data sources in accordance with the disclosed embodiments;

FIGS. 7A-7D illustrate a series of user interface screens for an example data model-driven report generation interface in accordance with the disclosed embodiments;

FIG. 8 illustrates an example search query received from a client and executed by search peers in accordance with the disclosed embodiments;

FIG. 9A illustrates a key indicators view in accordance with the disclosed embodiments;

FIG. 9B illustrates an incident review dashboard in accordance with the disclosed embodiments;

FIG. 9C illustrates a proactive monitoring tree in accordance with the disclosed embodiments;

FIG. 9D illustrates a user interface screen displaying both log data and performance data in accordance with the disclosed embodiments;

FIG. 10 illustrates a block diagram of an example cloud-based data intake and query system in which an embodiment may be implemented;

FIG. 11 illustrates a block diagram of an example data intake and query system that performs searches across external data systems in accordance with the disclosed embodiments;

FIGS. 12-14 illustrate a series of user interface screens for an example data model-driven report generation interface in accordance with the disclosed embodiments;

FIGS. 15-17 illustrate example visualizations generated by a reporting application in accordance with the disclosed embodiments;

FIG. 18 illustrates a block diagram of an example pipeline manager in which an embodiment may be implemented;

FIG. 19 illustrates a block diagram of an example search head in which an embodiment may be implemented;

FIG. 20 is a flow diagram that illustrates how a pipeline may be processed in accordance with the disclosed embodiments;

FIGS. 21 and 22 are another set of flow diagrams that illustrates how a pipeline may be processed in accordance with the disclosed embodiments; and

FIGS. 23A and 23B are examples of processing a search query in accordance with the disclosed embodiments.

DETAILED DESCRIPTION

Specific embodiments of the invention will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency.

In the following detailed description of embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as by the use of the terms “before”, “after”, “single”, and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.

Further, although the description includes a discussion of various embodiments of the invention, the various disclosed embodiments may be combined in virtually any manner. All combinations are contemplated herein.

In general, embodiments of the invention are directed to partially typed semantic optimization. In particular, an initial pipeline is received having a sequence of commands. One or more embodiments build an abstract semantic tree (AST) from the initial pipeline using semantic information about each command. The semantic information may be complete or incomplete with respect to each command. Complete semantic information includes all semantics for the command which incomplete semantic information means that at least one piece of semantic information is unknown. For at least one command, the semantic information is incomplete resulting in incomplete information in the AST. Even though the AST has incomplete semantic information, one or more embodiments manipulate the AST to create a revised AST that corresponds to a revised pipeline. The revised pipeline reduces the execution time from the initial pipeline. Thus, the revised pipeline is executed instead of the initial pipeline.

Embodiments are described herein according to the following outline:

-   1.0. General Overview -   2.0. Operating Environment     -   2.1. Host Devices     -   2.2. Client Devices     -   2.3. Client Device Applications     -   2.4. Data Server System     -   2.5. Data Ingestion         -   2.5.1. Input         -   2.5.2. Parsing         -   2.5.3. Indexing     -   2.6. Query Processing     -   2.7. Field Extraction     -   2.8. Example Search Screen     -   2.9. Data Modelling     -   2.10. Acceleration Techniques         -   2.10.1. Aggregation Technique         -   2.10.2. Keyword Index         -   2.10.3. High Performance Analytics Store         -   2.10.4. Accelerating Report Generation     -   2.11. Security Features     -   2.12. Data Center Monitoring     -   2.13. Cloud-Based System Overview     -   2.14. Searching Externally Archived Data         -   2.14.1. ERP Process Features -   3.0 Data Manipulation Pipeline Optimization -   4.0 Hardware

1.0. General Overview

Modern data centers and other computing environments can comprise anywhere from a few host computer systems to thousands of systems configured to process data, service requests from remote clients, and perform numerous other computational tasks. During operation, various components within these computing environments often generate significant volumes of machine-generated data. For example, machine data is generated by various components in the information technology (IT) environments, such as servers, sensors, routers, mobile devices, Internet of Things (IoT) devices, etc. Machine-generated data can include system logs, network packet data, sensor data, application program data, error logs, stack traces, system performance data, etc. In general, machine-generated data can also include performance data, diagnostic information, and many other types of data that can be analyzed to diagnose performance problems, monitor user interactions, and to derive other insights.

A number of tools are available to analyze machine data, that is, machine-generated data. In order to reduce the size of the potentially vast amount of machine data that may be generated, many of these tools typically pre-process the data based on anticipated data-analysis needs. For example, pre-specified data items may be extracted from the machine data and stored in a database to facilitate efficient retrieval and analysis of those data items at search time. However, the rest of the machine data typically is not saved and discarded during pre-processing. As storage capacity becomes progressively cheaper and more plentiful, there are fewer incentives to discard these portions of machine data and many reasons to retain more of the data.

This plentiful storage capacity is presently making it feasible to store massive quantities of minimally processed machine data for later retrieval and analysis. In general, storing minimally processed machine data and performing analysis operations at search time can provide greater flexibility because it enables an analyst to search all of the machine data, instead of searching only a pre-specified set of data items. This may enable an analyst to investigate different aspects of the machine data that previously were unavailable for analysis.

However, analyzing and searching massive quantities of machine data presents a number of challenges. For example, a data center, servers, or network appliances may generate many different types and formats of machine data (e.g., system logs, network packet data (e.g., wire data, etc.), sensor data, application program data, error logs, stack traces, system performance data, operating system data, virtualization data, etc.) from thousands of different components, which can collectively be very time-consuming to analyze. In another example, mobile devices may generate large amounts of information relating to data accesses, application performance, operating system performance, network performance, etc. There can be millions of mobile devices that report these types of information.

These challenges can be addressed by using an event-based data intake and query system, such as the SPLUNK® ENTERPRISE system developed by Splunk Inc. of San Francisco, Calif. The SPLUNK® ENTERPRISE system is the leading platform for providing real-time operational intelligence that enables organizations to collect, index, and search machine-generated data from various websites, applications, servers, networks, and mobile devices that power their businesses. The SPLUNK® ENTERPRISE system is particularly useful for analyzing data which is commonly found in system log files, network data, and other data input sources. Although many of the techniques described herein are explained with reference to a data intake and query system similar to the SPLUNK® ENTERPRISE system, these techniques are also applicable to other types of data systems.

In the SPLUNK® ENTERPRISE system, machine-generated data are collected and stored as “events”. An event comprises a portion of the machine-generated data and is associated with a specific point in time. For example, events may be derived from “time series data,” where the time series data comprises a sequence of data points (e.g., performance measurements from a computer system, etc.) that are associated with successive points in time. In general, each event can be associated with a timestamp that is derived from the raw data in the event, determined through interpolation between temporally proximate events having known timestamps, or determined based on other configurable rules for associating timestamps with events, etc.

In some instances, machine data can have a predefined format, where data items with specific data formats are stored at predefined locations in the data. For example, the machine data may include data stored as fields in a database table. In other instances, machine data may not have a predefined format, that is, the data is not at fixed, predefined locations, but the data does have repeatable patterns and is not random. This means that some machine data can comprise various data items of different data types and that may be stored at different locations within the data. For example, when the data source is an operating system log, an event can include one or more lines from the operating system log containing raw data that includes different types of performance and diagnostic information associated with a specific point in time.

Examples of components which may generate machine data from which events can be derived include, but are not limited to, web servers, application servers, databases, firewalls, routers, operating systems, and software applications that execute on computer systems, mobile devices, sensors, Internet of Things (IoT) devices, etc. The data generated by such data sources can include, for example and without limitation, server log files, activity log files, configuration files, messages, network packet data, performance measurements, sensor measurements, etc.

The SPLUNK® ENTERPRISE system uses flexible schema to specify how to extract information from the event data. A flexible schema may be developed and redefined as needed. Note that a flexible schema may be applied to event data “on the fly,” when it is needed (e.g., at search time, index time, ingestion time, etc.). When the schema is not applied to event data until search time it may be referred to as a “late-binding schema.”

During operation, the SPLUNK® ENTERPRISE system starts with raw input data (e.g., one or more system logs, streams of network packet data, sensor data, application program data, error logs, stack traces, system performance data, etc.). The system divides this raw data into blocks (e.g., buckets of data, each associated with a specific time frame, etc.), and parses the raw data to produce timestamped events. The system stores the timestamped events in a data store. The system enables users to run queries against the stored data to, for example, retrieve events that meet criteria specified in a query, such as containing certain keywords or having specific values in defined fields. As used herein throughout, data that is part of an event is referred to as “event data”. In this context, the term “field” refers to a location in the event data containing one or more values for a specific data item. As will be described in more detail herein, the fields are defined by extraction rules (e.g., regular expressions) that derive one or more values from the portion of raw machine data in each event that has a particular field specified by an extraction rule. The set of values so produced are semantically-related (such as IP address), even though the raw machine data in each event may be in different formats (e.g., semantically-related values may be in different positions in the events derived from different sources).

As noted above, the SPLUNK® ENTERPRISE system utilizes a late-binding schema to event data while performing queries on events. One aspect of a late-binding schema is applying “extraction rules” to event data to extract values for specific fields during search time. More specifically, the extraction rules for a field can include one or more instructions that specify how to extract a value for the field from the event data. An extraction rule can generally include any type of instruction for extracting values from data in events. In some cases, an extraction rule comprises a regular expression where a sequence of characters form a search pattern, in which case the rule is referred to as a “regex rule.” The system applies the regex rule to the event data to extract values for associated fields in the event data by searching the event data for the sequence of characters defined in the regex rule.

In the SPLUNK® ENTERPRISE system, a field extractor may be configured to automatically generate extraction rules for certain field values in the events when the events are being created, indexed, or stored, or possibly at a later time. Alternatively, a user may manually define extraction rules for fields using a variety of techniques. In contrast to a conventional schema for a database system, a late-binding schema is not defined at data ingestion time. Instead, the late-binding schema can be developed on an ongoing basis until the time a query is actually executed. This means that extraction rules for the fields in a query may be provided in the query itself, or may be located during execution of the query. Hence, as a user learns more about the data in the events, the user can continue to refine the late-binding schema by adding new fields, deleting fields, or modifying the field extraction rules for use the next time the schema is used by the system. Because the SPLUNK® ENTERPRISE system maintains the underlying raw data and uses late-binding schema for searching the raw data, it enables a user to continue investigating and learn valuable insights about the raw data.

In some embodiments, a common field name may be used to reference two or more fields containing equivalent data items, even though the fields may be associated with different types of events that possibly have different data formats and different extraction rules. By enabling a common field name to be used to identify equivalent fields from different types of events generated by disparate data sources, the system facilitates use of a “common information model” (CIM) across the disparate data sources (further discussed with respect to FIG. 5 ).

2.0. Operating Environment

FIG. 1 illustrates a networked computer system 100 in which an embodiment may be implemented. Those skilled in the art would understand that FIG. 1 represents one example of a networked computer system and other embodiments may use different arrangements.

The networked computer system 100 comprises one or more computing devices. These one or more computing devices comprise any combination of hardware and software configured to implement the various logical components described herein. For example, the one or more computing devices may include one or more memories that store instructions for implementing the various components described herein, one or more hardware processors configured to execute the instructions stored in the one or more memories, and various data repositories in the one or more memories for storing data structures utilized and manipulated by the various components.

In an embodiment, one or more client devices 102 are coupled to one or more host devices 106 and a data intake and query system 108 via one or more networks 104. Networks 104 broadly represent one or more LANs, WANs, cellular networks (e.g., LTE, HSPA, 3G, and other cellular technologies), and/or networks using any of wired, wireless, terrestrial microwave, or satellite links, and may include the public Internet.

2.1. Host Devices

In the illustrated embodiment, a system 100 includes one or more host devices 106. Host devices 106 may broadly include any number of computers, virtual machine instances, and/or data centers that are configured to host or execute one or more instances of host applications 114. In general, a host device 106 may be involved, directly or indirectly, in processing requests received from client devices 102. Each host device 106 may comprise, for example, one or more of a network device, a web server, an application server, a database server, etc. A collection of host devices 106 may be configured to implement a network-based service. For example, a provider of a network-based service may configure one or more host devices 106 and host applications 114 (e.g., one or more web servers, application servers, database servers, etc.) to collectively implement the network-based application.

In general, client devices 102 communicate with one or more host applications 114 to exchange information. The communication between a client device 102 and a host application 114 may, for example, be based on the Hypertext Transfer Protocol (HTTP) or any other network protocol. Content delivered from the host application 114 to a client device 102 may include, for example, HTML documents, media content, etc. The communication between a client device 102 and host application 114 may include sending various requests and receiving data packets. For example, in general, a client device 102 or application running on a client device may initiate communication with a host application 114 by making a request for a specific resource (e.g., based on an HTTP request), and the application server may respond with the requested content stored in one or more response packets.

In the illustrated embodiment, one or more of host applications 114 may generate various types of performance data during operation, including event logs, network data, sensor data, and other types of machine-generated data. For example, a host application 114 comprising a web server may generate one or more web server logs in which details of interactions between the web server and any number of client devices 102 is recorded. As another example, a host device 106 comprising a router may generate one or more router logs that record information related to network traffic managed by the router. As yet another example, a host application 114 comprising a database server may generate one or more logs that record information related to requests sent from other host applications 114 (e.g., web servers or application servers) for data managed by the database server.

2.2. Client Devices

Client devices 102 of FIG. 1 represent any computing device capable of interacting with one or more host devices 106 via a network 104. Examples of client devices 102 may include, without limitation, smart phones, tablet computers, handheld computers, wearable devices, laptop computers, desktop computers, servers, portable media players, gaming devices, and so forth. In general, a client device 102 can provide access to different content, for instance, content provided by one or more host devices 106, etc. Each client device 102 may comprise one or more client applications 110, described in more detail in a separate section hereinafter.

2.3. Client Device Applications

In an embodiment, each client device 102 may host or execute one or more client applications 110 that are capable of interacting with one or more host devices 106 via one or more networks 104. For instance, a client application 110 may be or comprise a web browser that a user may use to navigate to one or more websites or other resources provided by one or more host devices 106. As another example, a client application 110 may comprise a mobile application or “app.” For example, an operator of a network-based service hosted by one or more host devices 106 may make available one or more mobile apps that enable users of client devices 102 to access various resources of the network-based service. As yet another example, client applications 110 may include background processes that perform various operations without direct interaction from a user. A client application 110 may include a “plug-in” or “extension” to another application, such as a web browser plug-in or extension.

In an embodiment, a client application 110 may include a monitoring component 112. At a high level, the monitoring component 112 comprises a software component or other logic that facilitates generating performance data related to a client device's operating state, including monitoring network traffic sent and received from the client device and collecting other device and/or application-specific information. Monitoring component 112 may be an integrated component of a client application 110, a plug-in, an extension, or any other type of add-on component. Monitoring component 112 may also be a stand-alone process.

In one embodiment, a monitoring component 112 may be created when a client application 110 is developed, for example, by an application developer using a software development kit (SDK). The SDK may include custom monitoring code that can be incorporated into the code implementing a client application 110. When the code is converted to an executable application, the custom code implementing the monitoring functionality can become part of the application itself.

In some cases, an SDK or other code for implementing the monitoring functionality may be offered by a provider of a data intake and query system, such as a system 108. In such cases, the provider of the system 108 can implement the custom code so that performance data generated by the monitoring functionality is sent to the system 108 to facilitate analysis of the performance data by a developer of the client application or other users.

In an embodiment, the custom monitoring code may be incorporated into the code of a client application 110 in a number of different ways, such as the insertion of one or more lines in the client application code that call or otherwise invoke the monitoring component 112. As such, a developer of a client application 110 can add one or more lines of code into the client application 110 to trigger the monitoring component 112 at desired points during execution of the application. Code that triggers the monitoring component may be referred to as a monitor trigger. For instance, a monitor trigger may be included at or near the beginning of the executable code of the client application 110 such that the monitoring component 112 is initiated or triggered as the application is launched, or included at other points in the code that correspond to various actions of the client application, such as sending a network request or displaying a particular interface.

In an embodiment, the monitoring component 112 may monitor one or more aspects of network traffic sent and/or received by a client application 110. For example, the monitoring component 112 may be configured to monitor data packets transmitted to and/or from one or more host applications 114. Incoming and/or outgoing data packets can be read or examined to identify network data contained within the packets, for example, and other aspects of data packets can be analyzed to determine a number of network performance statistics. Monitoring network traffic may enable information to be gathered particular to the network performance associated with a client application 110 or set of applications.

In an embodiment, network performance data refers to any type of data that indicates information about the network and/or network performance. Network performance data may include, for instance, a URL requested, a connection type (e.g., HTTP, HTTPS, etc.), a connection start time, a connection end time, an HTTP status code, request length, response length, request headers, response headers, connection status (e.g., completion, response time(s), failure, etc.), and the like. Upon obtaining network performance data indicating performance of the network, the network performance data can be transmitted to a data intake and query system 108 for analysis.

Upon developing a client application 110 that incorporates a monitoring component 112, the client application 110 can be distributed to client devices 102. Applications generally can be distributed to client devices 102 in any manner, or they can be pre-loaded. In some cases, the application may be distributed to a client device 102 via an application marketplace or other application distribution system. For instance, an application marketplace or other application distribution system might distribute the application to a client device based on a request from the client device to download the application.

Examples of functionality that enables monitoring performance of a client device are described in U.S. patent application Ser. No. 14/524,748, entitled “UTILIZING PACKET HEADERS TO MONITOR NETWORK TRAFFIC IN ASSOCIATION WITH A CLIENT DEVICE”, filed on 27 Oct. 2014, and which is hereby incorporated by reference in its entirety for all purposes.

In an embodiment, the monitoring component 112 may also monitor and collect performance data related to one or more aspects of the operational state of a client application 110 and/or client device 102. For example, a monitoring component 112 may be configured to collect device performance information by monitoring one or more client device operations, or by making calls to an operating system and/or one or more other applications executing on a client device 102 for performance information. Device performance information may include, for instance, a current wireless signal strength of the device, a current connection type and network carrier, current memory performance information, a geographic location of the device, a device orientation, and any other information related to the operational state of the client device.

In an embodiment, the monitoring component 112 may also monitor and collect other device profile information including, for example, a type of client device, a manufacturer and model of the device, versions of various software applications installed on the device, and so forth.

In general, a monitoring component 112 may be configured to generate performance data in response to a monitor trigger in the code of a client application 110 or other triggering application event, as described above, and to store the performance data in one or more data records. Each data record, for example, may include a collection of field-value pairs, each field-value pair storing a particular item of performance data in association with a field for the item. For example, a data record generated by a monitoring component 112 may include a “networkLatency” field (not shown in the Figure) in which a value is stored. This field indicates a network latency measurement associated with one or more network requests. The data record may include a “state” field to store a value indicating a state of a network connection, and so forth for any number of aspects of collected performance data.

2.4. Data Server System

FIG. 2 depicts a block diagram of an exemplary data intake and query system 108, similar to the SPLUNK® ENTERPRISE system. All or a portion of system 108 may be implemented as a computing system. System 108 includes one or more forwarders 204 that receive data from a variety of input data sources 202, and one or more indexers 206 that process and store the data in one or more data stores 208. These forwarders and indexers can comprise separate computer systems, or may alternatively comprise separate processes executing on one or more computer systems.

Each data source 202 broadly represents a distinct source of data that can be consumed by a system 108. Examples of a data source 202 include, without limitation, data files, directories of files, data sent over a network, event logs, registries, etc.

During operation, the forwarders 204 identify which indexers 206 receive data collected from a data source 202 and forward the data to the appropriate indexers. Forwarders 204 can also perform operations on the data before forwarding, including removing extraneous data, detecting timestamps in the data, parsing data, indexing data, routing data based on criteria relating to the data being routed, and/or performing other data transformations.

In an embodiment, a forwarder 204 may comprise a service accessible to client devices 102 and host devices 106 via a network 104. For example, one type of forwarder 204 may be capable of consuming vast amounts of real-time data from a potentially large number of client devices 102 and/or host devices 106. The forwarder 204 may, for example, comprise a computing device which implements multiple pipelines or “queues” to handle forwarding of network data to indexers 206. A forwarder 204 may also perform many of the functions that are performed by an indexer. For example, a forwarder 204 may perform keyword extractions on raw data or parse raw data to create events. A forwarder 204 may generate time stamps for events. Additionally, or alternatively, a forwarder 204 may perform routing of events to indexers. Data store 208 may contain events derived from machine data from a variety of sources all pertaining to the same component in an IT environment, and this data may be produced by the machine in question or by other components in the IT environment.

2.5. Data Ingestion

FIG. 3 depicts a flow chart illustrating an example data flow performed by Data Intake and Query system 108, in accordance with the disclosed embodiments. The data flow illustrated in FIG. 3 is provided for illustrative purposes only; those skilled in the art would understand that one or more of the steps of the processes illustrated in FIG. 3 may be removed or the ordering of the steps may be changed. Furthermore, for the purposes of illustrating a clear example, one or more particular system components are described in the context of performing various operations during each of the data flow stages. For example, a forwarder is described as receiving and processing data during an input phase; an indexer is described as parsing and indexing data during parsing and indexing phases; and a search head is described as performing a search query during a search phase. However, other system arrangements and distributions of the processing steps across system components may be used.

2.5.1. Input

At block 302, a forwarder receives data from an input source, such as a data source 202 shown in FIG. 2 . A forwarder initially may receive the data as a raw data stream generated by the input source. For example, a forwarder may receive a data stream from a log file generated by an application server, from a stream of network data from a network device, or from any other source of data. In one embodiment, a forwarder receives the raw data and may segment the data stream into “blocks”, or “buckets,” possibly of a uniform data size, to facilitate subsequent processing steps.

At block 304, a forwarder or other system component annotates each block generated from the raw data with one or more metadata fields. These metadata fields may, for example, provide information related to the data block as a whole and may apply to each event that is subsequently derived from the data in the data block. For example, the metadata fields may include separate fields specifying each of a host, a source, and a source type related to the data block. A host field may contain a value identifying a host name or IP address of a device that generated the data. A source field may contain a value identifying a source of the data, such as a pathname of a file or a protocol and port related to received network data. A source type field may contain a value specifying a particular source type label for the data. Additional metadata fields may also be included during the input phase, such as a character encoding of the data, if known, and possibly other values that provide information relevant to later processing steps. In an embodiment, a forwarder forwards the annotated data blocks to another system component (typically an indexer) for further processing.

The SPLUNK® ENTERPRISE system allows forwarding of data from one SPLUNK® ENTERPRISE instance to another, or even to a third-party system. SPLUNK® ENTERPRISE system can employ different types of forwarders in a configuration.

In an embodiment, a forwarder may contain the essential components needed to forward data. It can gather data from a variety of inputs and forward the data to a SPLUNK® ENTERPRISE server for indexing and searching. It also can tag metadata (e.g., source, source type, host, etc.).

Additionally, or optionally, in an embodiment, a forwarder has the capabilities of the aforementioned forwarder as well as additional capabilities. The forwarder can parse data before forwarding the data (e.g., associate a time stamp with a portion of data and create an event, etc.) and can route data based on criteria such as source or type of event. It can also index data locally while forwarding the data to another indexer.

2.5.2. Parsing

At block 306, an indexer receives data blocks from a forwarder and parses the data to organize the data into events. In an embodiment, to organize the data into events, an indexer may determine a source type associated with each data block (e.g., by extracting a source type label from the metadata fields associated with the data block, etc.) and refer to a source type configuration corresponding to the identified source type. The source type definition may include one or more properties that indicate to the indexer to automatically determine the boundaries of events within the data. In general, these properties may include regular expression-based rules or delimiter rules where, for example, event boundaries may be indicated by predefined characters or character strings. These predefined characters may include punctuation marks or other special characters including, for example, carriage returns, tabs, spaces, line breaks, etc. If a source type for the data is unknown to the indexer, an indexer may infer a source type for the data by examining the structure of the data. Then, it can apply an inferred source type definition to the data to create the events.

At block 308, the indexer determines a timestamp for each event. Similar to the process for creating events, an indexer may again refer to a source type definition associated with the data to locate one or more properties that indicate instructions for determining a timestamp for each event. The properties may, for example, instruct an indexer to extract a time value from a portion of data in the event, to interpolate time values based on timestamps associated with temporally proximate events, to create a timestamp based on a time the event data was received or generated, to use the timestamp of a previous event, or use any other rules for determining timestamps.

At block 310, the indexer associates with each event one or more metadata fields including a field containing the timestamp (in some embodiments, a timestamp may be included in the metadata fields) determined for the event. These metadata fields may include a number of “default fields” that are associated with all events, and may also include one more custom fields as defined by a user. Similar to the metadata fields associated with the data blocks at block 304, the default metadata fields associated with each event may include a host, source, and source type field including or in addition to a field storing the timestamp.

At block 312, an indexer may optionally apply one or more transformations to data included in the events created at block 306. For example, such transformations can include removing a portion of an event (e.g., a portion used to define event boundaries, extraneous characters from the event, other extraneous text, etc.), masking a portion of an event (e.g., masking a credit card number), removing redundant portions of an event, etc. The transformations applied to event data may, for example, be specified in one or more configuration files and referenced by one or more source type definitions.

2.5.3. Indexing

At blocks 314 and 316, an indexer can optionally generate a keyword index to facilitate fast keyword searching for event data. To build a keyword index, at block 314, the indexer identifies a set of keywords in each event. At block 316, the indexer includes the identified keywords in an index, which associates each stored keyword with reference pointers to events containing that keyword (or to locations within events where that keyword is located, other location identifiers, etc.). When an indexer subsequently receives a keyword-based query, the indexer can access the keyword index to quickly identify events containing the keyword.

In some embodiments, the keyword index may include entries for name-value pairs found in events, where a name-value pair can include a pair of keywords connected by a symbol, such as an equals sign or colon. This way, events containing these name-value pairs can be quickly located. In some embodiments, fields can automatically be generated for some or all of the name-value pairs at the time of indexing. For example, if the string “dest=10.0.1.2” is found in an event, a field named “dest” may be created for the event, and assigned a value of “10.0.1.2”.

At block 318, the indexer stores the events with an associated timestamp in a data store 208. Timestamps enable a user to search for events based on a time range. In one embodiment, the stored events are organized into “buckets,” where each bucket stores events associated with a specific time range based on the timestamps associated with each event. This may not only improve time-based searching, but also allows for events with recent timestamps, which may have a higher likelihood of being accessed, to be stored in a faster memory to facilitate faster retrieval. For example, buckets containing the most recent events can be stored in flash memory rather than on a hard disk.

Each indexer 206 may be responsible for storing and searching a subset of the events contained in a corresponding data store 208. By distributing events among the indexers and data stores, the indexers can analyze events for a query in parallel. For example, using map-reduce techniques, each indexer returns partial responses for a subset of events to a search head that combines the results to produce an answer for the query. By storing events in buckets for specific time ranges, an indexer may further optimize data retrieval process by searching buckets corresponding to time ranges that are relevant to a query.

Moreover, events and buckets can also be replicated across different indexers and data stores to facilitate high availability and disaster recovery as described in U.S. patent application Ser. No. 14/266,812, entitled “Site-Based Search Affinity”, filed on 30 Apr. 2014, and in U.S. patent application Ser. No. 14/266,817, entitled “Multi-Site Clustering”, also filed on 30 Apr. 2014, each of which is hereby incorporated by reference in its entirety for all purposes.

2.6. Query Processing

FIG. 4 is a flow diagram that illustrates an exemplary process that a search head and one or more indexers may perform during a search query. At block 402, a search head receives a search query from a client. At block 404, the search head analyzes the search query to determine what portion(s) of the query can be delegated to indexers and what portions of the query can be executed locally by the search head. At block 406, the search head distributes the determined portions of the query to the appropriate indexers. In an embodiment, a search head cluster may take the place of an independent search head where each search head in the search head cluster coordinates with peer search heads in the search head cluster to schedule jobs, replicate search results, update configurations, fulfill search requests, etc. In an embodiment, the search head (or each search head) communicates with a master node (also known as a cluster master, not shown in FIG.) that provides the search head with a list of indexers to which the search head can distribute the determined portions of the query. The master node maintains a list of active indexers and can also designate which indexers may have responsibility for responding to queries over certain sets of events. A search head may communicate with the master node before the search head distributes queries to indexers to discover the addresses of active indexers.

At block 408, the indexers to which the query was distributed, search data stores associated with them for events that are responsive to the query. To determine which events are responsive to the query, the indexer searches for events that match the criteria specified in the query. These criteria can include matching keywords or specific values for certain fields. The searching operations at block 408 may use the late-binding schema to extract values for specified fields from events at the time the query is processed. In an embodiment, one or more rules for extracting field values may be specified as part of a source type definition. The indexers may then either send the relevant events back to the search head, or use the events to determine a partial result, and send the partial result back to the search head.

At block 410, the search head combines the partial results and/or events received from the indexers to produce a final result for the query. This final result may comprise different types of data depending on what the query requested. For example, the results can include a listing of matching events returned by the query, or some type of visualization of the data from the returned events. In another example, the final result can include one or more calculated values derived from the matching events.

The results generated by the system 108 can be returned to a client using different techniques. For example, one technique streams results or relevant events back to a client in real-time as they are identified. Another technique waits to report the results to the client until a complete set of results (which may include a set of relevant events or a result based on relevant events) is ready to return to the client. Yet another technique streams interim results or relevant events back to the client in real-time until a complete set of results is ready, and then returns the complete set of results to the client. In another technique, certain results are stored as “search jobs” and the client may retrieve the results by referring the search jobs.

The search head can also perform various operations to make the search more efficient. For example, before the search head begins execution of a query, the search head can determine a time range for the query and a set of common keywords that all matching events include. The search head may then use these parameters to query the indexers to obtain a superset of the eventual results. Then, during a filtering stage, the search head can perform field-extraction operations on the superset to produce a reduced set of search results. This speeds up queries that are performed on a periodic basis.

2.7. Field Extraction

The search head 210 allows users to search and visualize event data extracted from raw machine data received from homogenous data sources. It also allows users to search and visualize event data extracted from raw machine data received from heterogeneous data sources. The search head 210 includes various mechanisms, which may additionally reside in an indexer 206, for processing a query. Splunk Processing Language (SPL), used in conjunction with the SPLUNK® ENTERPRISE system, can be utilized to make a query. SPL is a pipeline search language in which a set of inputs is operated on by a first command in a command line, and then a subsequent command following the pipe symbol “I” operates on the results produced by the first command, and so on for additional commands. Other query languages, such as the Structured Query Language (“SQL”), can be used to create a query.

In response to receiving the search query, search head 210 uses extraction rules to extract values for the fields associated with a field or fields in the event data being searched. The search head 210 obtains extraction rules that specify how to extract a value for certain fields from an event. Extraction rules can comprise regex rules that specify how to extract values for the relevant fields. In addition to specifying how to extract field values, the extraction rules may also include instructions for deriving a field value by performing a function on a character string or value retrieved by the extraction rule. For example, a transformation rule may truncate a character string, or convert the character string into a different data format. In some cases, the query itself can specify one or more extraction rules.

The search head 210 can apply the extraction rules to event data that it receives from indexers 206. Indexers 206 may apply the extraction rules to events in an associated data store 208. Extraction rules can be applied to all the events in a data store, or to a subset of the events that have been filtered based on some criteria (e.g., event time stamp values, etc.). Extraction rules can be used to extract one or more values for a field from events by parsing the event data and examining the event data for one or more patterns of characters, numbers, delimiters, etc., that indicate where the field begins and, optionally, ends.

FIG. 5 illustrates an example of raw machine data received from disparate data sources. In this example, a user submits an order for merchandise using a vendor's shopping application program 501 running on the user's system. In this example, the order was not delivered to the vendor's server due to a resource exception at the destination server that is detected by the middleware code 502. The user then sends a message to the customer support 503 to complain about the order failing to complete. The three systems 501, 502, and 503 are disparate systems that do not have a common logging format. The order application 501 sends log data 504 to the SPLUNK® ENTERPRISE system in one format, the middleware code 502 sends error log data 505 in a second format, and the support server 503 sends log data 506 in a third format.

Using the log data received at one or more indexers 206 from the three systems the vendor can uniquely obtain an insight into user activity, user experience, and system behavior. The search head 210 allows the vendor's administrator to search the log data from the three systems that one or more indexers 206 are responsible for searching, thereby obtaining correlated information, such as the order number and corresponding customer ID number of the person placing the order. The system also allows the administrator to see a visualization of related events via a user interface. The administrator can query the search head 210 for customer ID field value matches across the log data from the three systems that are stored at the one or more indexers 206. The customer ID field value exists in the data gathered from the three systems, but the customer ID field value may be located in different areas of the data given differences in the architecture of the systems—there is a semantic relationship between the customer ID field values generated by the three systems. The search head 210 requests event data from the one or more indexers 206 to gather relevant event data from the three systems. It then applies extraction rules to the event data in order to extract field values that it can correlate. The search head may apply a different extraction rule to each set of events from each system when the event data format differs among systems. In this example, the user interface can display to the administrator the event data corresponding to the common customer ID field values 507, 508, and 509, thereby providing the administrator with insight into a customer's experience.

Note that query results can be returned to a client, a search head, or any other system component for further processing. In general, query results may include a set of one or more events, a set of one or more values obtained from the events, a subset of the values, statistics calculated based on the values, a report containing the values, or a visualization, such as a graph or chart, generated from the values.

2.8. Example Search Screen

FIG. 6A illustrates an example search screen 600 in accordance with the disclosed embodiments. Search screen 600 includes a search bar 602 that accepts user input in the form of a search string. It also includes a time range picker 612 that enables the user to specify a time range for the search. For “historical searches” the user can select a specific time range, or alternatively a relative time range, such as “today,” “yesterday” or “last week.” For “real-time searches,” the user can select the size of a preceding time window to search for real-time events. Search screen 600 also initially displays a “data summary” dialog as is illustrated in FIG. 6B that enables the user to select different sources for the event data, such as by selecting specific hosts and log files.

After the search is executed, the search screen 600 in FIG. 6A can display the results through search results tabs 604, wherein search results tabs 604 includes: an “events tab” that displays various information about events returned by the search; a “statistics tab” that displays statistics about the search results; and a “visualization tab” that displays various visualizations of the search results. The events tab illustrated in FIG. 6A displays a timeline graph 605 that graphically illustrates the number of events that occurred in one-hour intervals over the selected time range. It also displays an events list 608 that enables a user to view the raw data in each of the returned events. It additionally displays a fields sidebar 606 that includes statistics about occurrences of specific fields in the returned events, including “selected fields” that are pre-selected by the user, and “interesting fields” that are automatically selected by the system based on pre-specified criteria.

2.9. Data Models

A data model is a hierarchically structured search-time mapping of semantic knowledge about one or more datasets. It encodes the domain knowledge necessary to build a variety of specialized searches of those datasets. Those searches, in turn, can be used to generate reports.

A data model is composed of one or more “objects” (or “data model objects”) that define or otherwise correspond to a specific set of data.

Objects in data models can be arranged hierarchically in parent/child relationships. Each child object represents a subset of the dataset covered by its parent object. The top-level objects in data models are collectively referred to as “root objects.”

Child objects have inheritance. Data model objects are defined by characteristics that mostly break down into constraints and attributes. Child objects inherit constraints and attributes from their parent objects and have additional constraints and attributes of their own. Child objects provide a way of filtering events from parent objects. Because a child object always provides an additional constraint in addition to the constraints it has inherited from its parent object, the dataset it represents is always a subset of the dataset that its parent represents.

For example, a first data model object may define a broad set of data pertaining to e-mail activity generally, and another data model object may define specific datasets within the broad dataset, such as a subset of the e-mail data pertaining specifically to e-mails sent. Examples of data models can include electronic mail, authentication, databases, intrusion detection, malware, application state, alerts, compute inventory, network sessions, network traffic, performance, audits, updates, vulnerabilities, etc. Data models and their objects can be designed by knowledge managers in an organization, and they can enable downstream users to quickly focus on a specific set of data. For example, a user can simply select an “e-mail activity” data model object to access a dataset relating to e-mails generally (e.g., sent or received), or select an “e-mails sent” data model object (or data sub-model object) to access a dataset relating to e-mails sent.

A data model object may be defined by (1) a set of search constraints, and (2) a set of fields. Thus, a data model object can be used to quickly search data to identify a set of events and to identify a set of fields to be associated with the set of events. For example, an “e-mails sent” data model object may specify a search for events relating to e-mails that have been sent, and specify a set of fields that are associated with the events. Thus, a user can retrieve and use the “e-mails sent” data model object to quickly search source data for events relating to sent e-mails, and may be provided with a listing of the set of fields relevant to the events in a user interface screen.

A child of the parent data model may be defined by a search (typically a narrower search) that produces a subset of the events that would be produced by the parent data model's search. The child's set of fields can include a subset of the set of fields of the parent data model and/or additional fields. Data model objects that reference the subsets can be arranged in a hierarchical manner, so that child subsets of events are proper subsets of their parents. A user iteratively applies a model development tool (not shown in FIG.) to prepare a query that defines a subset of events and assigns an object name to that subset. A child subset is created by further limiting a query that generated a parent subset. A late-binding schema of field extraction rules is associated with each object or subset in the data model.

Data definitions in associated schemas can be taken from the common information model (CIM) or can be devised for a particular schema and optionally added to the CIM. Child objects inherit fields from parents and can include fields not present in parents. A model developer can select fewer extraction rules than are available for the sources returned by the query that defines events belonging to a model. Selecting a limited set of extraction rules can be a tool for simplifying and focusing the data model, while allowing a user flexibility to explore the data subset. Development of a data model is further explained in U.S. Pat. Nos. 8,788,525 and 8,788,526, both entitled “DATA MODEL FOR MACHINE DATA FOR SEMANTIC SEARCH”, both issued on 22 Jul. 2014, U.S. Pat. No. 8,983,994, entitled “GENERATION OF A DATA MODEL FOR SEARCHING MACHINE DATA”, issued on 17 Mar. 2015, U.S. patent application Ser. No. 14/611,232, entitled “GENERATION OF A DATA MODEL APPLIED TO QUERIES”, filed on 31 Jan. 2015, and U.S. patent application Ser. No. 14/815,884, entitled “GENERATION OF A DATA MODEL APPLIED TO OBJECT QUERIES”, filed on 31 Jul. 2015, each of which is hereby incorporated by reference in its entirety for all purposes. See, also, Knowledge Manager Manual, Build a Data Model, Splunk Enterprise 6.1.3 pp. 150-204 (Aug. 25, 2014).

A data model can also include reports. One or more report formats can be associated with a particular data model and be made available to run against the data model. A user can use child objects to design reports with object datasets that already have extraneous data pre-filtered out. In an embodiment, the data intake and query system 108 provides the user with the ability to produce reports (e.g., a table, chart, visualization, etc.) without having to enter SPL, SQL, or other query language terms into a search screen. Data models are used as the basis for the search feature.

Data models may be selected in a report generation interface. The report generator supports drag-and-drop organization of fields to be summarized in a report. When a model is selected, the fields with available extraction rules are made available for use in the report. The user may refine and/or filter search results to produce more precise reports. The user may select some fields for organizing the report and select other fields for providing detail according to the report organization. For example, “region” and “salesperson” are fields used for organizing the report and sales data can be summarized (subtotaled and totaled) within this organization. The report generator allows the user to specify one or more fields within events and apply statistical analysis on values extracted from the specified one or more fields. The report generator may aggregate search results across sets of events and generate statistics based on aggregated search results. Building reports using the report generation interface is further explained in U.S. patent application Ser. No. 14/503,335, entitled “GENERATING REPORTS FROM UNSTRUCTURED DATA”, filed on 30 Sep. 2014, and which is hereby incorporated by reference in its entirety for all purposes, and in Pivot Manual, Splunk Enterprise 6.1.3 (Aug. 4, 2014). Data visualizations also can be generated in a variety of formats, by reference to the data model. Reports, data visualizations, and data model objects can be saved and associated with the data model for future use. The data model object may be used to perform searches of other data.

FIGS. 12, 13, and 7A-7D illustrate a series of user interface screens where a user may select report generation options using data models. The report generation process may be driven by a predefined data model object, such as a data model object defined and/or saved via a reporting application or a data model object obtained from another source. A user can load a saved data model object using a report editor. For example, the initial search query and fields used to drive the report editor may be obtained from a data model object. The data model object that is used to drive a report generation process may define a search and a set of fields. Upon loading of the data model object, the report generation process may enable a user to use the fields (e.g., the fields defined by the data model object) to define criteria for a report (e.g., filters, split rows/columns, aggregates, etc.) and the search may be used to identify events (e.g., to identify events responsive to the search) used to generate the report. That is, for example, if a data model object is selected to drive a report editor, the graphical user interface of the report editor may enable a user to define reporting criteria for the report using the fields associated with the selected data model object, and the events used to generate the report may be constrained to the events that match, or otherwise satisfy, the search constraints of the selected data model object.

The selection of a data model object for use in driving a report generation may be facilitated by a data model object selection interface. FIG. 12 illustrates an example interactive data model selection graphical user interface 1200 of a report editor that displays a listing of available data models 1201. The user may select one of the data models 1202.

FIG. 13 illustrates an example data model object selection graphical user interface 1300 that displays available data objects 1301 for the selected data object model 1202. The user may select one of the displayed data model objects 1302 for use in driving the report generation process.

Once a data model object is selected by the user, a user interface screen 700 shown in FIG. 7A may display an interactive listing of automatic field identification options 701 based on the selected data model object. For example, a user may select one of the three illustrated options (e.g., the “All Fields” option 702, the “Selected Fields” option 703, or the “Coverage” option (e.g., fields with at least a specified % of coverage) 704). If the user selects the “All Fields” option 702, all of the fields identified from the events that were returned in response to an initial search query may be selected. That is, for example, all of the fields of the identified data model object fields may be selected. If the user selects the “Selected Fields” option 703, only the fields from the fields of the identified data model object fields that are selected by the user may be used. If the user selects the “Coverage” option 704, only the fields of the identified data model object fields meeting a specified coverage criteria may be selected. A percent coverage may refer to the percentage of events returned by the initial search query that a given field appears in. Thus, for example, if an object dataset includes 10,000 events returned in response to an initial search query, and the “avg_age” field appears in 854 of those 10,000 events, then the “avg_age” field would have a coverage of 8.54% for that object dataset. If, for example, the user selects the “Coverage” option and specifies a coverage value of 2%, only fields having a coverage value equal to or greater than 2% may be selected. The number of fields corresponding to each selectable option may be displayed in association with each option. For example, “97” displayed next to the “All Fields” option 702 indicates that 97 fields will be selected if the “All Fields” option is selected. The “3” displayed next to the “Selected Fields” option 703 indicates that 3 of the 97 fields will be selected if the “Selected Fields” option is selected. The “49” displayed next to the “Coverage” option 704 indicates that 49 of the 97 fields (e.g., the 49 fields having a coverage of 2% or greater) will be selected if the “Coverage” option is selected. The number of fields corresponding to the “Coverage” option may be dynamically updated based on the specified percent of coverage.

FIG. 7B illustrates an example graphical user interface screen (also called the pivot interface) 705 displaying the reporting application's “Report Editor” page. The screen may display interactive elements for defining various elements of a report. For example, the page includes a “Filters” element 706, a “Split Rows” element 707, a “Split Columns” element 708, and a “Column Values” element 709. The page may include a list of search results 711. In this example, the Split Rows element 707 is expanded, revealing a listing of fields 710 that can be used to define additional criteria (e.g., reporting criteria). The listing of fields 710 may correspond to the selected fields (attributes). That is, the listing of fields 710 may list only the fields previously selected, either automatically and/or manually by a user. FIG. 7C illustrates a formatting dialogue 712 that may be displayed upon selecting a field from the listing of fields 710. The dialogue can be used to format the display of the results of the selection (e.g., label the column to be displayed as “component”).

FIG. 7D illustrates an example graphical user interface screen 705 including a table of results 713 based on the selected criteria including splitting the rows by the “component” field. A column 714 having an associated count for each component listed in the table may be displayed that indicates an aggregate count of the number of times that the particular field-value pair (e.g., the value in a row) occurs in the set of events responsive to the initial search query.

FIG. 14 illustrates an example graphical user interface screen 1400 that allows the user to filter search results and to perform statistical analysis on values extracted from specific fields in the set of events. In this example, the top ten product names ranked by price are selected as a filter 1401 that causes the display of the ten most popular products sorted by price. Each row is displayed by product name and price 1402. This results in each product displayed in a column labeled “product name” along with an associated price in a column labeled “price” 1406. Statistical analysis of other fields in the events associated with the ten most popular products has been specified as column values 1403. A count of the number of successful purchases for each product is displayed in column 1404. This statistic may be produced by filtering the search results by the product name, finding all occurrences of a successful purchase in a field within the events and generating a total of the number of occurrences. A sum of the total sales is displayed in column 1405, which is a result of the multiplication of the price and the number of successful purchases for each product.

The reporting application allows the user to create graphical visualizations of the statistics generated for a report. For example, FIG. 15 illustrates an example graphical user interface 1500 that displays a set of components and associated statistics 1501. The reporting application allows the user to select a visualization of the statistics in a graph (e.g., bar chart, scatter plot, area chart, line chart, pie chart, radial gauge, marker gauge, filler gauge, etc.). FIG. 16 illustrates an example of a bar chart visualization 1600 of an aspect of the statistical data 1501. FIG. 17 illustrates a scatter plot visualization 1700 of an aspect of the statistical data 1501.

2.10. Acceleration Technique

The above-described system provides significant flexibility by enabling a user to analyze massive quantities of minimally processed data “on the fly” at search time instead of storing pre-specified portions of the data in a database at ingestion time. This flexibility enables a user to see valuable insights, correlate data, and perform subsequent queries to examine interesting aspects of the data that may not have been apparent at ingestion time.

However, performing extraction and analysis operations at search time can involve a large amount of data and require a large number of computational operations, which can cause delays in processing the queries. Advantageously, SPLUNK® ENTERPRISE system employs a number of unique acceleration techniques that have been developed to speed up analysis operations performed at search time. These techniques include: (1) performing search operations in parallel across multiple indexers; (2) using a keyword index; (3) using a high-performance analytics store; and (4) accelerating the process of generating reports. These novel techniques are described in more detail below.

2.10.1. Aggregation Technique

To facilitate faster query processing, a query can be structured such that multiple indexers perform the query in parallel, while aggregation of search results from the multiple indexers is performed locally at the search head. For example, FIG. 8 illustrates how a search query 802 received from a client at a search head 210 can split into two phases, including: (1) subtasks 804 (e.g., data retrieval or simple filtering) that may be performed in parallel by indexers 206 for execution, and (2) a search results aggregation operation 806 to be executed by the search head when the results are ultimately collected from the indexers.

During operation, upon receiving search query 802, a search head 210 determines that a portion of the operations involved with the search query may be performed locally by the search head. The search head modifies search query 802 by substituting “stats” (create aggregate statistics over results sets received from the indexers at the search head) with “prestats” (create statistics by the indexer from local results set) to produce search query 804, and then distributes search query 804 to distributed indexers, which are also referred to as “search peers.” Note that search queries may generally specify search criteria or operations to be performed on events that meet the search criteria. Search queries may also specify field names, as well as search criteria for the values in the fields or operations to be performed on the values in the fields. Moreover, the search head may distribute the full search query to the search peers as illustrated in FIG. 4 , or may alternatively distribute a modified version (e.g., a more restricted version) of the search query to the search peers. In this example, the indexers are responsible for producing the results and sending them to the search head. After the indexers return the results to the search head, the search head aggregates the received results 806 to form a single search result set. By executing the query in this manner, the system effectively distributes the computational operations across the indexers while minimizing data transfers.

2.10.2. Keyword Index

As described above with reference to the flow charts in FIG. 3 and FIG. 4 , data intake and query system 108 can construct and maintain one or more keyword indices to quickly identify events containing specific keywords. This technique can greatly speed up the processing of queries involving specific keywords. As mentioned above, to build a keyword index, an indexer first identifies a set of keywords. Then, the indexer includes the identified keywords in an index, which associates each stored keyword with references to events containing that keyword, or to locations within events where that keyword is located. When an indexer subsequently receives a keyword-based query, the indexer can access the keyword index to quickly identify events containing the keyword.

2.10.3. High Performance Analytics Store

To speed up certain types of queries, some embodiments of system 108 create a high-performance analytics store, which is referred to as a “summarization table,” that contains entries for specific field-value pairs. Each of these entries keeps track of instances of a specific value in a specific field in the event data and includes references to events containing the specific value in the specific field. For example, an example entry in a summarization table can keep track of occurrences of the value “94107” in a “ZIP code” field of a set of events and the entry includes references to all of the events that contain the value “94107” in the ZIP code field. This optimization technique enables the system to quickly process queries that seek to determine how many events have a particular value for a particular field. To this end, the system can examine the entry in the summarization table to count instances of the specific value in the field without having to go through the individual events or perform data extractions at search time. Also, if the system needs to process all events that have a specific field-value combination, the system can use the references in the summarization table entry to directly access the events to extract further information without having to search all of the events to find the specific field-value combination at search time.

In some embodiments, the system maintains a separate summarization table for each of the above-described time-specific buckets that stores events for a specific time range. A bucket-specific summarization table includes entries for specific field-value combinations that occur in events in the specific bucket. Alternatively, the system can maintain a separate summarization table for each indexer. The indexer-specific summarization table includes entries for the events in a data store that are managed by the specific indexer. Indexer-specific summarization tables may also be bucket-specific.

The summarization table can be populated by running a periodic query that scans a set of events to find instances of a specific field-value combination, or alternatively instances of all field-value combinations for a specific field. A periodic query can be initiated by a user, or can be scheduled to occur automatically at specific time intervals. A periodic query can also be automatically launched in response to a query that asks for a specific field-value combination.

In some cases, when the summarization tables may not cover all of the events that are relevant to a query, the system can use the summarization tables to obtain partial results for the events that are covered by summarization tables, but may also have to search through other events that are not covered by the summarization tables to produce additional results. These additional results can then be combined with the partial results to produce a final set of results for the query. The summarization table and associated techniques are described in more detail in U.S. Pat. No. 8,682,925, entitled “Distributed High Performance Analytics Store”, issued on 25 Mar. 2014, U.S. patent application Ser. No. 14/170,159, entitled “SUPPLEMENTING A HIGH PERFORMANCE ANALYTICS STORE WITH EVALUATION OF INDIVIDUAL EVENTS TO RESPOND TO AN EVENT QUERY”, filed on 31 Jan. 2014, and U.S. patent application Ser. No. 14/815,973, entitled “STORAGE MEDIUM AND CONTROL DEVICE”, filed on 21 Feb. 2014, each of which is hereby incorporated by reference in its entirety.

2.10.4. Accelerating Report Generation

In some embodiments, a data server system such as the SPLUNK® ENTERPRISE system can accelerate the process of periodically generating updated reports based on query results. To accelerate this process, a summarization engine automatically examines the query to determine whether generation of updated reports can be accelerated by creating intermediate summaries. If reports can be accelerated, the summarization engine periodically generates a summary covering data obtained during a latest non-overlapping time period. For example, where the query seeks events meeting a specified criterion, a summary for the time period includes only events within the time period that meet the specified criteria. Similarly, if the query seeks statistics calculated from the events, such as the number of events that match the specified criteria, then the summary for the time period includes the number of events in the period that match the specified criteria.

In addition to the creation of the summaries, the summarization engine schedules the periodic updating of the report associated with the query. During each scheduled report update, the query engine determines whether intermediate summaries have been generated covering portions of the time period covered by the report update. If so, then the report is generated based on the information contained in the summaries. Also, if additional event data has been received and has not yet been summarized, and is required to generate the complete report, the query can be run on this additional event data. Then, the results returned by this query on the additional event data, along with the partial results obtained from the intermediate summaries, can be combined to generate the updated report. This process is repeated each time the report is updated. Alternatively, if the system stores events in buckets covering specific time ranges, then the summaries can be generated on a bucket-by-bucket basis. Note that producing intermediate summaries can save the work involved in re-running the query for previous time periods, so advantageously only the newer event data needs to be processed while generating an updated report. These report acceleration techniques are described in more detail in U.S. Pat. No. 8,589,403, entitled “Compressed Journaling In Event Tracking Files For Metadata Recovery And Replication”, issued on 19 Nov. 2013, U.S. Pat. No. 8,412,696, entitled “Real Time Searching And Reporting”, issued on 2 Apr. 2011, and U.S. Pat. Nos. 8,589,375 and 8,589,432, both also entitled “REAL TIME SEARCHING AND REPORTING”, both issued on 19 Nov. 2013, each of which is hereby incorporated by reference in its entirety.

2.11. Security Features

The SPLUNK® ENTERPRISE platform provides various schemas, dashboards and visualizations that simplify developers' task to create applications with additional capabilities. One such application is the SPLUNK® APP FOR ENTERPRISE SECURITY, which performs monitoring and alerting operations and includes analytics to facilitate identifying both known and unknown security threats based on large volumes of data stored by the SPLUNK® ENTERPRISE system. SPLUNK® APP FOR ENTERPRISE SECURITY provides the security practitioner with visibility into security-relevant threats found in the enterprise infrastructure by capturing, monitoring, and reporting on data from enterprise security devices, systems, and applications. Through the use of SPLUNK® ENTERPRISE searching and reporting capabilities, SPLUNK® APP FOR ENTERPRISE SECURITY provides a top-down and bottom-up view of an organization's security posture.

The SPLUNK® APP FOR ENTERPRISE SECURITY leverages SPLUNK® ENTERPRISE search-time normalization techniques, saved searches, and correlation searches to provide visibility into security-relevant threats and activity and generate notable events for tracking. The App enables the security practitioner to investigate and explore the data to find new or unknown threats that do not follow signature-based patterns.

Conventional Security Information and Event Management (SIEM) systems that lack the infrastructure to effectively store and analyze large volumes of security-related data. Traditional SIEM systems typically use fixed schemas to extract data from pre-defined security-related fields at data ingestion time and storing the extracted data in a relational database. This traditional data extraction process (and associated reduction in data size) that occurs at data ingestion time inevitably hampers future incident investigations that may need original data to determine the root cause of a security issue, or to detect the onset of an impending security threat.

In contrast, the SPLUNK® APP FOR ENTERPRISE SECURITY system stores large volumes of minimally processed security-related data at ingestion time for later retrieval and analysis at search time when a live security threat is being investigated. To facilitate this data retrieval process, the SPLUNK® APP FOR ENTERPRISE SECURITY provides pre-specified schemas for extracting relevant values from the different types of security-related event data and enables a user to define such schemas.

The SPLUNK® APP FOR ENTERPRISE SECURITY can process many types of security-related information. In general, this security-related information can include any information that can be used to identify security threats. For example, the security-related information can include network-related information, such as IP addresses, domain names, asset identifiers, network traffic volume, uniform resource locator strings, and source addresses. The process of detecting security threats for network-related information is further described in U.S. Pat. No. 8,826,434, entitled “SECURITY THREAT DETECTION BASED ON INDICATIONS IN BIG DATA OF ACCESS TO NEWLY REGISTERED DOMAINS”, issued on 2 Sep. 2014, U.S. patent application Ser. No. 13/956,252, entitled “INVESTIGATIVE AND DYNAMIC DETECTION OF POTENTIAL SECURITY-THREAT INDICATORS FROM EVENTS IN BIG DATA”, filed on 31 Jul. 2013, U.S. patent application Ser. No. 14/445,018, entitled “GRAPHIC DISPLAY OF SECURITY THREATS BASED ON INDICATIONS OF ACCESS TO NEWLY REGISTERED DOMAINS”, filed on 28 Jul. 2014, U.S. patent application Ser. No. 14/445,023, entitled “SECURITY THREAT DETECTION OF NEWLY REGISTERED DOMAINS”, filed on 28 Jul. 2014, U.S. patent application Ser. No. 14/815,971, entitled “SECURITY THREAT DETECTION USING DOMAIN NAME ACCESSES”, filed on 1 Aug. 2015, and U.S. patent application Ser. No. 14/815,972, entitled “SECURITY THREAT DETECTION USING DOMAIN NAME REGISTRATIONS”, filed on 1 Aug. 2015, each of which is hereby incorporated by reference in its entirety for all purposes. Security-related information can also include malware infection data and system configuration information, as well as access control information, such as login/logout information and access failure notifications. The security-related information can originate from various sources within a data center, such as hosts, virtual machines, storage devices and sensors. The security-related information can also originate from various sources in a network, such as routers, switches, email servers, proxy servers, gateways, firewalls and intrusion-detection systems.

During operation, the SPLUNK® APP FOR ENTERPRISE SECURITY facilitates detecting “notable events” that are likely to indicate a security threat. These notable events can be detected in a number of ways: (1) a user can notice a correlation in the data and can manually identify a corresponding group of one or more events as “notable;” or (2) a user can define a “correlation search” specifying criteria for a notable event, and every time one or more events satisfy the criteria, the application can indicate that the one or more events are notable. A user can alternatively select a pre-defined correlation search provided by the application. Note that correlation searches can be run continuously or at regular intervals (e.g., every hour) to search for notable events. Upon detection, notable events can be stored in a dedicated “notable events index,” which can be subsequently accessed to generate various visualizations containing security-related information. Also, alerts can be generated to notify system operators when important notable events are discovered.

The SPLUNK® APP FOR ENTERPRISE SECURITY provides various visualizations to aid in discovering security threats, such as a “key indicators view” that enables a user to view security metrics, such as counts of different types of notable events. For example, FIG. 9A illustrates an example key indicators view 900 that comprises a dashboard, which can display a value 901, for various security-related metrics, such as malware infections 902. It can also display a change in a metric value 903, which indicates that the number of malware infections increased by 63 during the preceding interval. Key indicators view 900 additionally displays a histogram panel 904 that displays a histogram of notable events organized by urgency values, and a histogram of notable events organized by time intervals. This key indicators view is described in further detail in pending U.S. patent application Ser. No. 13/956,338, entitled “Key Indicators View”, filed on 31 Jul. 2013, and which is hereby incorporated by reference in its entirety for all purposes.

These visualizations can also include an “incident review dashboard” that enables a user to view and act on “notable events.” These notable events can include: (1) a single event of high importance, such as any activity from a known web attacker; or (2) multiple events that collectively warrant review, such as a large number of authentication failures on a host followed by a successful authentication. For example, FIG. 9B illustrates an example incident review dashboard 910 that includes a set of incident attribute fields 911 that, for example, enables a user to specify a time range field 912 for the displayed events. It also includes a timeline 913 that graphically illustrates the number of incidents that occurred in time intervals over the selected time range. It additionally displays an events list 914 that enables a user to view a list of all of the notable events that match the criteria in the incident attributes fields 911. To facilitate identifying patterns among the notable events, each notable event can be associated with an urgency value (e.g., low, medium, high, critical), which is indicated in the incident review dashboard. The urgency value for a detected event can be determined based on the severity of the event and the priority of the system component associated with the event.

2.12. Data Center Monitoring

As mentioned above, the SPLUNK® ENTERPRISE platform provides various features that simplify the developer's task to create various applications. One such application is SPLUNK® APP FOR VMWARE® that provides operational visibility into granular performance metrics, logs, tasks and events, and topology from hosts, virtual machines and virtual centers. It empowers administrators with an accurate real-time picture of the health of the environment, proactively identifying performance and capacity bottlenecks.

Conventional data-center-monitoring systems lack the infrastructure to effectively store and analyze large volumes of machine-generated data, such as performance information and log data obtained from the data center. In conventional data-center-monitoring systems, machine-generated data is typically pre-processed prior to being stored, for example, by extracting pre-specified data items and storing them in a database to facilitate subsequent retrieval and analysis at search time. However, the rest of the data is not saved and discarded during pre-processing.

In contrast, the SPLUNK® APP FOR VMWARE® stores large volumes of minimally processed machine data, such as performance information and log data, at ingestion time for later retrieval and analysis at search time when a live performance issue is being investigated. In addition to data obtained from various log files, this performance-related information can include values for performance metrics obtained through an application programming interface (API) provided as part of the vSphere Hypervisor™ system distributed by VMware, Inc. of Palo Alto, Calif. For example, these performance metrics can include: (1) CPU-related performance metrics; (2) disk-related performance metrics; (3) memory-related performance metrics; (4) network-related performance metrics; (5) energy-usage statistics; (6) data-traffic-related performance metrics; (7) overall system availability performance metrics; (8) cluster-related performance metrics; and (9) virtual machine performance statistics. Such performance metrics are described in U.S. patent application Ser. No. 14/167,316, entitled “Correlation For User-Selected Time Ranges Of Values For Performance Metrics Of Components In An Information-Technology Environment With Log Data From That Information-Technology Environment”, filed on 29 Jan. 2014, and which is hereby incorporated by reference in its entirety for all purposes.

U.S. Pat. No. 1,001,571 To facilitate retrieving information of interest from performance data and log files, the SPLUNK® APP FOR VMWARE® provides pre-specified schemas for extracting relevant values from different types of performance-related event data, and also enables a user to define such schemas.

The SPLUNK® APP FOR VMWARE® additionally provides various visualizations to facilitate detecting and diagnosing the root cause of performance problems. For example, one such visualization is a “proactive monitoring tree” that enables a user to easily view and understand relationships among various factors that affect the performance of a hierarchically structured computing system. This proactive monitoring tree enables a user to easily navigate the hierarchy by selectively expanding nodes representing various entities (e.g., virtual centers or computing clusters) to view performance information for lower-level nodes associated with lower-level entities (e.g., virtual machines or host systems). Example node-expansion operations are illustrated in FIG. 9C, wherein nodes 933 and 934 are selectively expanded. Note that nodes 931-939 can be displayed using different patterns or colors to represent different performance states, such as a critical state, a warning state, a normal state or an unknown/offline state. The ease of navigation provided by selective expansion in combination with the associated performance-state information enables a user to quickly diagnose the root cause of a performance problem. The proactive monitoring tree is described in further detail in U.S. patent application Ser. No. 14/253,490, entitled “PROACTIVE MONITORING TREE WITH SEVERITY STATE SORTING”, filed on 15 Apr. 2014, and U.S. patent application Ser. No. 14/812,948, also entitled “PROACTIVE MONITORING TREE WITH SEVERITY STATE SORTING”, filed on 29 Jul. 2015, each of which is hereby incorporated by reference in its entirety for all purposes.

The SPLUNK® APP FOR VMWARE® also provides a user interface that enables a user to select a specific time range and then view heterogeneous data comprising events, log data, and associated performance metrics for the selected time range. For example, the screen illustrated in FIG. 9D displays a listing of recent “tasks and events” and a listing of recent “log entries” for a selected time range above a performance-metric graph for “average CPU core utilization” for the selected time range. Note that a user is able to operate pull-down menus 942 to selectively display different performance metric graphs for the selected time range. This enables the user to correlate trends in the performance-metric graph with corresponding event and log data to quickly determine the root cause of a performance problem. This user interface is described in more detail in U.S. patent application Ser. No. 14/167,316, entitled “Correlation For User-Selected Time Ranges Of Values For Performance Metrics Of Components In An Information-Technology Environment With Log Data From That Information-Technology Environment”, filed on 29 Jan. 2014, and which is hereby incorporated by reference in its entirety for all purposes.

2.13. Cloud-Based System Overview

The example data intake and query system 108 described in reference to FIG. 2 comprises several system components, including one or more forwarders, indexers, and search heads. In some environments, a user of a data intake and query system 108 may install and configure, on computing devices owned and operated by the user, one or more software applications that implement some or all of these system components. For example, a user may install a software application on server computers owned by the user and configure each server to operate as one or more of a forwarder, an indexer, a search head, etc. This arrangement generally may be referred to as an “on-premises” solution. That is, the system 108 is installed and operates on computing devices directly controlled by the user of the system. Some users may prefer an on-premises solution because it may provide a greater level of control over the configuration of certain aspects of the system (e.g., security, privacy, standards, controls, etc.). However, other users may instead prefer an arrangement in which the user is not directly responsible for providing and managing the computing devices upon which various components of system 108 operate.

In one embodiment, to provide an alternative to an entirely on-premises environment for system 108, one or more of the components of a data intake and query system instead may be provided as a cloud-based service. In this context, a cloud-based service refers to a service hosted by one more computing resources that are accessible to end users over a network, for example, by using a web browser or other application on a client device to interface with the remote computing resources. For example, a service provider may provide a cloud-based data intake and query system by managing computing resources configured to implement various aspects of the system (e.g., forwarders, indexers, search heads, etc.) and by providing access to the system to end users via a network. Typically, a user may pay a subscription or other fee to use such a service. Each subscribing user of the cloud-based service may be provided with an account that enables the user to configure a customized cloud-based system based on the user's preferences.

FIG. 10 illustrates a block diagram of an example cloud-based data intake and query system. Similar to the system of FIG. 2 , the networked computer system 1000 includes input data sources 202 and forwarders 204. These input data sources and forwarders may be in a subscriber's private computing environment. Alternatively, they might be directly managed by the service provider as part of the cloud service. In the example system 1000, one or more forwarders 204 and client devices 1002 are coupled to a cloud-based data intake and query system 1006 via one or more networks 1004. Network 1004 broadly represents one or more LANs, WANs, cellular networks, intranet, internet, etc., using any of wired, wireless, terrestrial microwave, satellite links, etc., and may include the public Internet, and is used by client devices 1002 and forwarders 204 to access the system 1006. Similar to the system of 108, each of the forwarders 204 may be configured to receive data from an input source and to forward the data to other components of the system 1006 for further processing.

In an embodiment, a cloud-based data intake and query system 1006 may comprise a plurality of system instances 1008. In general, each system instance 1008 may include one or more computing resources managed by a provider of the cloud-based system 1006 made available to a particular subscriber. The computing resources comprising a system instance 1008 may, for example, include one or more servers or other devices configured to implement one or more forwarders, indexers, search heads, and other components of a data intake and query system, similar to system 108. As indicated above, a subscriber may use a web browser or other application of a client device 1002 to access a web portal or other interface that enables the subscriber to configure an instance 1008.

Providing a data intake and query system as described in reference to system 108 as a cloud-based service presents a number of challenges. Each of the components of a system 108 (e.g., forwarders, indexers and search heads) may at times refer to various configuration files stored locally at each component. These configuration files typically may involve some level of user configuration to accommodate particular types of data a user desires to analyze and to account for other user preferences. However, in a cloud-based service context, users typically may not have direct access to the underlying computing resources implementing the various system components (e.g., the computing resources comprising each system instance 1008) and may desire to make such configurations indirectly, for example, using one or more web-based interfaces. Thus, the techniques and systems described herein for providing user interfaces that enable a user to configure source type definitions are applicable to both on-premises and cloud-based service contexts, or some combination thereof (e.g., a hybrid system where both an on-premises environment such as SPLUNK® ENTERPRISE and a cloud-based environment such as SPLUNK CLOUD™ are centrally visible).

2.14. Searching Externally Archived Data

FIG. 11 shows a block diagram of an example of a data intake and query system 108 that provides transparent search facilities for data systems that are external to the data intake and query system. Such facilities are available in the HUNK® system provided by Splunk Inc. of San Francisco, Calif. HUNK® represents an analytics platform that enables business and IT teams to rapidly explore, analyze, and visualize data in Hadoop and NoSQL data stores.

The search head 210 of the data intake and query system receives search requests from one or more client devices 1104 over network connections 1120. As discussed above, the data intake and query system 108 may reside in an enterprise location, in the cloud, etc. FIG. 11 illustrates that multiple client devices 1104 a, 1104 b, . . . , 1104 n may communicate with the data intake and query system 108. The client devices 1104 may communicate with the data intake and query system using a variety of connections. For example, one client device in FIG. 11 is illustrated as communicating over an Internet (Web) protocol, another client device is illustrated as communicating via a command line interface, and another client device is illustrated as communicating via a system developer kit (SDK).

The search head 210 analyzes the received search request to identify request parameters. If a search request received from one of the client devices 1104 references an index maintained by the data intake and query system, then the search head 210 connects to one or more indexers 206 of the data intake and query system for the index referenced in the request parameters. That is, if the request parameters of the search request reference an index, then the search head accesses the data in the index via the indexer. The data intake and query system 108 may include one or more indexers 206, depending on system access resources and requirements. As described further below, the indexers 206 retrieve data from their respective local data stores 208 as specified in the search request. The indexers and their respective data stores can comprise one or more storage devices and typically reside on the same system, though they may be connected via a local network connection.

If the request parameters of the received search request reference an external data collection, which is not accessible to the indexers 206 or under the management of the data intake and query system, then the search head 210 can access the external data collection through an External Result Provider (ERP) process 1110. An external data collection may be referred to as a “virtual index” (plural, “virtual indices”). An ERP process provides an interface through which the search head 210 may access virtual indices.

Thus, a search reference to an index of the system relates to a locally stored and managed data collection. In contrast, a search reference to a virtual index relates to an externally stored and managed data collection, which the search head may access through one or more ERP processes 1110, 1112. FIG. 11 shows two ERP processes 1110, 1112 that connect to respective remote (external) virtual indices, which are indicated as a Hadoop or another system 1114 (e.g., Amazon S3, Amazon EMR, other Hadoop Compatible File Systems (HCFS), etc.) and a relational database management system (RDBMS) 1116. Other virtual indices may include other file organizations and protocols, such as Structured Query Language (SQL) and the like. The ellipses between the ERP processes 1110, 1112 indicate optional additional ERP processes of the data intake and query system 108. An ERP process may be a computer process that is initiated or spawned by the search head 210 and is executed by the search data intake and query system 108. Alternatively, or additionally, an ERP process may be a process spawned by the search head 210 on the same or different host system as the search head 210 resides.

The search head 210 may spawn a single ERP process in response to multiple virtual indices referenced in a search request, or the search head may spawn different ERP processes for different virtual indices. Generally, virtual indices that share common data configurations or protocols may share ERP processes. For example, all search query references to a Hadoop file system may be processed by the same ERP process, if the ERP process is suitably configured. Likewise, all search query references to an SQL database may be processed by the same ERP process. In addition, the search head may provide a common ERP process for common external data source types (e.g., a common vendor may utilize a common ERP process, even if the vendor includes different data storage system types, such as Hadoop and SQL). Common indexing schemes also may be handled by common ERP processes, such as flat text files or Weblog files.

The search head 210 determines the number of ERP processes to be initiated via the use of configuration parameters that are included in a search request message. Generally, there is a one-to-many relationship between an external results provider “family” and ERP processes. There is also a one-to-many relationship between an ERP process and corresponding virtual indices that are referred to in a search request. For example, using RDBMS, assume two independent instances of such a system by one vendor, such as one RDBMS for production and another RDBMS used for development. In such a situation, it is likely preferable (but optional) to use two ERP processes to maintain the independent operation as between production and development data. Both of the ERPs, however, will belong to the same family, because the two RDBMS system types are from the same vendor.

The ERP processes 1110, 1112 receive a search request from the search head 210. The search head may optimize the received search request for execution at the respective external virtual index. Alternatively, the ERP process may receive a search request as a result of analysis performed by the search head or by a different system process. The ERP processes 1110, 1112 can communicate with the search head 210 via conventional input/output routines (e.g., standard in/standard out, etc.). In this way, the ERP process receives the search request from a client device such that the search request may be efficiently executed at the corresponding external virtual index.

The ERP processes 1110, 1112 may be implemented as a process of the data intake and query system. Each ERP process may be provided by the data intake and query system, or may be provided by process or application providers who are independent of the data intake and query system. Each respective ERP process may include an interface application installed at a computer of the external result provider that ensures proper communication between the search support system and the external result provider. The ERP processes 1110, 1112 generate appropriate search requests in the protocol and syntax of the respective virtual indices 1114, 1116, each of which corresponds to the search request received by the search head 210. Upon receiving search results from their corresponding virtual indices, the respective ERP process passes the result to the search head 210, which may return or display the results or a processed set of results based on the returned results to the respective client device.

Client devices 1104 may communicate with the data intake and query system 108 through a network interface 1120, e.g., one or more LANs, WANs, cellular networks, intranet, and/or internet using any of wired, wireless, terrestrial microwave, satellite links, etc., and may include the public Internet.

The analytics platform utilizing the External Result Provider process described in more detail in U.S. Pat. No. 8,738,629, entitled “External Result Provided Process For Retrieving Data Stored Using A Different Configuration Or Protocol”, issued on 27 May 2014, U.S. Pat. No. 8,738,587, entitled “PROCESSING A SYSTEM SEARCH REQUEST BY RETRIEVING RESULTS FROM BOTH A NATIVE INDEX AND A VIRTUAL INDEX”, issued on 25 Jul. 2013, U.S. patent application Ser. No. 14/266,832, entitled “PROCESSING A SYSTEM SEARCH REQUEST ACROSS DISPARATE DATA COLLECTION SYSTEMS”, filed on 1 May 2014, and U.S. patent application Ser. No. 14/449,144, entitled “PROCESSING A SYSTEM SEARCH REQUEST INCLUDING EXTERNAL DATA SOURCES”, filed on 31 Jul. 2014, each of which is hereby incorporated by reference in its entirety for all purposes.

2.14.1. ERP Process Features

The ERP processes described above may include two operation modes: a streaming mode and a reporting mode. The ERP processes can operate in streaming mode only, in reporting mode only, or in both modes simultaneously. Operating in both modes simultaneously is referred to as mixed mode operation. In a mixed mode operation, the ERP at some point can stop providing the search head with streaming results and only provide reporting results thereafter, or the search head at some point may start ignoring streaming results it has been using and only use reporting results thereafter.

The streaming mode returns search results in real time, with minimal processing, in response to the search request. The reporting mode provides results of a search request with processing of the search results prior to providing them to the requesting search head, which in turn provides results to the requesting client device. ERP operation with such multiple modes provides greater performance flexibility with regard to report time, search latency, and resource utilization.

In a mixed mode operation, both streaming mode and reporting mode are operating simultaneously. The streaming mode results (e.g., the raw data obtained from the external data source) are provided to the search head, which can then process the results data (e.g., break the raw data into events, timestamp it, filter it, etc.) and integrate the results data with the results data from other external data sources, and/or from data stores of the search head. The search head performs such processing and can immediately start returning interim (streaming mode) results to the user at the requesting client device; simultaneously, the search head is waiting for the ERP process to process the data it is retrieving from the external data source as a result of the concurrently executing reporting mode.

In some instances, the ERP process initially operates in a mixed mode, such that the streaming mode operates to enable the ERP quickly to return interim results (e.g., some of the raw or unprocessed data necessary to respond to a search request) to the search head, enabling the search head to process the interim results and begin providing to the client or search requester interim results that are responsive to the query. Meanwhile, in this mixed mode, the ERP also operates concurrently in reporting mode, processing portions of raw data in a manner responsive to the search query. Upon determining that it has results from the reporting mode available to return to the search head, the ERP may halt processing in the mixed mode at that time (or some later time) by stopping the return of data in streaming mode to the search head and switching to reporting mode only. The ERP at this point starts sending interim results in reporting mode to the search head, which in turn may then present this processed data responsive to the search request to the client or search requester. Typically, the search head switches from using results from the ERP's streaming mode of operation to results from the ERP's reporting mode of operation when the higher bandwidth results from the reporting mode outstrip the amount of data processed by the search head in the streaming mode of ERP operation.

A reporting mode may have a higher bandwidth because the ERP does not have to spend time transferring data to the search head for processing all the raw data. In addition, the ERP may optionally direct another processor to do the processing.

The streaming mode of operation does not need to be stopped to gain the higher bandwidth benefits of a reporting mode; the search head could simply stop using the streaming mode results—and start using the reporting mode results—when the bandwidth of the reporting mode has caught up with or exceeded the amount of bandwidth provided by the streaming mode. Thus, a variety of triggers and ways to accomplish a search head's switch from using streaming mode results to using reporting mode results may be appreciated by one skilled in the art.

The reporting mode can involve the ERP process (or an external system) performing event breaking, time stamping, filtering of events to match the search query request, and calculating statistics on the results. The user can request particular types of data, such as if the search query itself involves types of events, or the search request may ask for statistics on data, such as on events that meet the search request. In either case, the search head understands the query language used in the received query request, which may be a proprietary language. One example query language is Splunk Processing Language (SPL) developed by the assignee of the application, Splunk Inc. The search head typically understands how to use that language to obtain data from the indexers, which store data in a format used by the SPLUNK® Enterprise system.

The ERP processes support the search head, as the search head is not ordinarily configured to understand the format in which data is stored in external data sources such as Hadoop or SQL data systems. Rather, the ERP process performs that translation from the query submitted in the search support system's native format (e.g., SPL if SPLUNK® ENTERPRISE is used as the search support system) to a search query request format that will be accepted by the corresponding external data system. The external data system typically stores data in a different format from that of the search support system's native index format, and it utilizes a different query language (e.g., SQL or MapReduce, rather than SPL or the like).

As noted, the ERP process can operate in the streaming mode alone. After the ERP process has performed the translation of the query request and received raw results from the streaming mode, the search head can integrate the returned data with any data obtained from local data sources (e.g., native to the search support system), other external data sources, and other ERP processes (if such operations were required to satisfy the terms of the search query). An advantage of mixed mode operation is that, in addition to streaming mode, the ERP process is also executing concurrently in reporting mode. Thus, the ERP process (rather than the search head) is processing query results (e.g., performing event breaking, timestamping, filtering, possibly calculating statistics if required to be responsive to the search query request, etc.). It should be apparent to those skilled in the art that additional time is needed for the ERP process to perform the processing in such a configuration. Therefore, the streaming mode will allow the search head to start returning interim results to the user at the client device before the ERP process can complete sufficient processing to start returning any search results. The switchover between streaming and reporting mode happens when the ERP process determines that the switchover is appropriate, such as when the ERP process determines it can begin returning meaningful results from its reporting mode.

The operation described above illustrates the source of operational latency: streaming mode has low latency (immediate results) and usually has relatively low bandwidth (fewer results can be returned per unit of time). In contrast, the concurrently running reporting mode has relatively high latency (it has to perform a lot more processing before returning any results) and usually has relatively high bandwidth (more results can be processed per unit of time). For example, when the ERP process does begin returning report results, it returns more processed results than in the streaming mode, because, e.g., statistics only need to be calculated to be responsive to the search request. That is, the ERP process doesn't have to take time to first return raw data to the search head. As noted, the ERP process could be configured to operate in streaming mode alone and return just the raw data for the search head to process in a way that is responsive to the search request. Alternatively, the ERP process can be configured to operate in the reporting mode only. Also, the ERP process can be configured to operate in streaming mode and reporting mode concurrently, as described, with the ERP process stopping the transmission of streaming results to the search head when the concurrently running reporting mode has caught up and started providing results. The reporting mode does not require the processing of all raw data that is responsive to the search query request before the ERP process starts returning results; rather, the reporting mode usually performs processing of chunks of events and returns the processing results to the search head for each chunk.

For example, an ERP process can be configured to merely return the contents of a search result file verbatim, with little or no processing of results. That way, the search head performs all processing (such as parsing byte streams into events, filtering, etc.). The ERP process can be configured to perform additional intelligence, such as analyzing the search request and handling all the computation that a native search indexer process would otherwise perform. In this way, the configured ERP process provides greater flexibility in features while operating according to desired preferences, such as response latency and resource requirements.

2.14. IT Service Monitoring

As previously mentioned, the SPLUNK® ENTERPRISE platform provides various schemas, dashboards and visualizations that make it easy for developers to create applications to provide additional capabilities. One such application is SPLUNK® IT SERVICE INTELLIGENCE™, which performs monitoring and alerting operations. It also includes analytics to help an analyst diagnose the root cause of performance problems based on large volumes of data stored by the SPLUNK® ENTERPRISE system as correlated to the various services an IT organization provides (a service-centric view). This differs significantly from conventional IT monitoring systems that lack the infrastructure to effectively store and analyze large volumes of service-related event data. Traditional service monitoring systems typically use fixed schemas to extract data from pre-defined fields at data ingestion time, wherein the extracted data is typically stored in a relational database. This data extraction process and associated reduction in data content that occurs at data ingestion time inevitably hampers future investigations, when all of the original data may be needed to determine the root cause of or contributing factors to a service issue.

In contrast, a SPLUNK® IT SERVICE INTELLIGENCE™ system stores large volumes of minimally-processed service-related data at ingestion time for later retrieval and analysis at search time, to perform regular monitoring, or to investigate a service issue. To facilitate this data retrieval process, SPLUNK® IT SERVICE INTELLIGENCE™ enables a user to define an IT operations infrastructure from the perspective of the services it provides. In this service-centric approach, a service such as corporate e-mail may be defined in terms of the entities employed to provide the service, such as host machines and network devices. Each entity is defined to include information for identifying all of the event data that pertains to the entity, whether produced by the entity itself or by another machine, and considering the many various ways the entity may be identified in raw machine data (such as by a URL, an IP address, or machine name). The service and entity definitions can organize event data around a service so that all of the event data pertaining to that service can be easily identified. This capability provides a foundation for the implementation of Key Performance Indicators.

One or more Key Performance Indicators (KPI's) are defined for a service within the SPLUNK® IT SERVICE INTELLIGENCE™ application. Each KPI measures an aspect of service performance at a point in time or over a period of time (aspect KPI's). Each KPI is defined by a search query that derives a KPI value from the machine data of events associated with the entities that provide the service. Information in the entity definitions may be used to identify the appropriate events at the time a KPI is defined or whenever a KPI value is being determined. The KPI values derived over time may be stored to build a valuable repository of current and historical performance information for the service, and the repository, itself, may be subject to search query processing. Aggregate KPIs may be defined to provide a measure of service performance calculated from a set of service aspect KPI values; this aggregate may even be taken across defined timeframes and/or across multiple services. A particular service may have an aggregate KPI derived from substantially all of the aspect KPI's of the service to indicate an overall health score for the service.

SPLUNK® IT SERVICE INTELLIGENCE™ facilitates the production of meaningful aggregate KPI's through a system of KPI thresholds and state values. Different KPI definitions may produce values in different ranges, and so the same value may mean something very different from one KPI definition to another. To address this, SPLUNK® IT SERVICE INTELLIGENCE™ implements a translation of individual KPI values to a common domain of “state” values. For example, a KPI range of values may be 1-100, or 50-275, while values in the state domain may be ‘critical,’ ‘warning,’ ‘normal,’ and ‘informational’. Thresholds associated with a particular KPI definition determine ranges of values for that KPI that correspond to the various state values. In one case, KPI values 95-100 may be set to correspond to ‘critical’ in the state domain. KPI values from disparate KPI's can be processed uniformly once they are translated into the common state values using the thresholds. For example, “normal 80% of the time” can be applied across various KPI's. To provide meaningful aggregate KPI's, a weighting value can be assigned to each KPI so that its influence on the calculated aggregate KPI value is increased or decreased relative to the other KPI's.

One service in an IT environment often impacts, or is impacted by, another service. SPLUNK® IT SERVICE INTELLIGENCE™ can reflect these dependencies. For example, a dependency relationship between a corporate e-mail service and a centralized authentication service can be reflected by recording an association between their respective service definitions. The recorded associations establish a service dependency topology that informs the data or selection options presented in a GUI, for example. (The service dependency topology is like a “map” showing how services are connected based on their dependencies.) The service topology may itself be depicted in a GUI and may be interactive to allow navigation among related services.

Entity definitions in SPLUNK® IT SERVICE INTELLIGENCE™ can include informational fields that can serve as metadata, implied data fields, or attributed data fields for the events identified by other aspects of the entity definition. Entity definitions in SPLUNK® IT SERVICE INTELLIGENCE™ can also be created and updated by an import of tabular data (as represented in a CSV, another delimited file, or a search query result set). The import may be GUI-mediated or processed using import parameters from a GUI-based import definition process. Entity definitions in SPLUNK® IT SERVICE INTELLIGENCE™ can also be associated with a service by means of a service definition rule. Processing the rule results in the matching entity definitions being associated with the service definition. The rule can be processed at creation time, and thereafter on a scheduled or on-demand basis. This allows dynamic, rule-based updates to the service definition.

During operation, SPLUNK® IT SERVICE INTELLIGENCE™ can recognize so-called “notable events” that may indicate a service performance problem or other situation of interest. These notable events can be recognized by a “correlation search” specifying trigger criteria for a notable event: every time KPI values satisfy the criteria, the application indicates a notable event. A severity level for the notable event may also be specified. Furthermore, when trigger criteria are satisfied, the correlation search may additionally or alternatively cause a service ticket to be created in an IT service management (ITSM) system, such as a system available from ServiceNow, Inc., of Santa Clara, Calif.

SPLUNK® IT SERVICE INTELLIGENCE™ provides various visualizations built on its service-centric organization of event data and the KPI values generated and collected. Visualizations can be particularly useful for monitoring or investigating service performance. SPLUNK® IT SERVICE INTELLIGENCE™ provides a service monitoring interface suitable as the home page for ongoing IT service monitoring. The interface is appropriate for settings such as desktop use or for a wall-mounted display in a network operations center (NOC). The interface may prominently display a services health section with tiles for the aggregate KPI's indicating overall health for defined services and a general KPI section with tiles for KPI's related to individual service aspects. These tiles may display KPI information in a variety of ways, such as by being colored and ordered according to factors like the KPI state value. They also can be interactive and navigate to visualizations of more detailed KPI information.

SPLUNK® IT SERVICE INTELLIGENCE™ provides a service-monitoring dashboard visualization based on a user-defined template. The template can include user-selectable widgets of varying types and styles to display KPI information. The content and the appearance of widgets can respond dynamically to changing KPI information. The KPI widgets can appear in conjunction with a background image, user drawing objects, or other visual elements, that depict the IT operations environment, for example. The KPI widgets or other GUI elements can be interactive so as to provide navigation to visualizations of more detailed KPI information.

SPLUNK® IT SERVICE INTELLIGENCE™ provides a visualization showing detailed time-series information for multiple KPI's in parallel graph lanes. The length of each lane can correspond to a uniform time range, while the width of each lane may be automatically adjusted to fit the displayed KPI data. Data within each lane may be displayed in a user selectable style, such as a line, area, or bar chart. During operation, a user may select a position in the time range of the graph lanes to activate lane inspection at that point in time. Lane inspection may display an indicator for the selected time across the graph lanes and display the KPI value associated with that point in time for each of the graph lanes. The visualization may also provide navigation to an interface for defining a correlation search, using information from the visualization to pre-populate the definition.

SPLUNK® IT SERVICE INTELLIGENCE™ provides a visualization for incident review showing detailed information for notable events. The incident review visualization may also show summary information for the notable events over a time frame, such as an indication of the number of notable events at each of a number of severity levels. The severity level display may be presented as a rainbow chart with the warmest color associated with the highest severity classification. The incident review visualization may also show summary information for the notable events over a time frame, such as the number of notable events occurring within segments of the time frame. The incident review visualization may display a list of notable events within the time frame ordered by any number of factors, such as time or severity. The selection of a particular notable event from the list may display detailed information about that notable event, including an identification of the correlation search that generated the notable event.

SPLUNK® IT SERVICE INTELLIGENCE™ provides pre-specified schemas for extracting relevant values from the different types of service-related event data. It also enables a user to define such schemas.

3.0 Data Manipulation Pipeline Optimization

Turning to FIG. 18 , FIG. 18 shows a pipeline manager 1800 in accordance with one or more embodiments of the invention. The pipeline manager 1800 is implemented on or may be a computing system, and includes functionality to receive and execute pipelines. In general, a pipeline is a sequence of commands, whereby each command is in a particular order. Each command in the sequence is ordered such that the output of a previous command is an input to the next command. For example, the output of the immediately preceding command may be the input to the immediate next commend. The particular order is preset prior to execution. Thus, the order of the commands in the sequence is independent of the execution.

In one or more embodiments, the pipeline is defined by an end user and submitted to an end user application. For example, the pipeline may be submitted via a text box. Each command in the sequence of commands has a command identifier and any parameters of the command. The command identifier uniquely identifies a type of command to perform. In other words, the command identifier identifies the set of instructions to perform. The parameters are any input controls specifying how to perform the operation. Execution of the command may further use input data. The input data may be the results of the previously processed command.

By way of an example, consider the scenario in which a data set has the attributes a, b, and c, where each event in the data set has a value for attributes a, b, and c. The data set may have been acquired through execution of a prior command in the pipeline. In such a scenario, a command in the pipeline may be “Add (a, c, d)”, where the last parameter of the add command refers to the location of storage, and the first two parameters refers to the values to add. In such a scenario, the command identifier is “Add”, the parameters are “a,” “c,” and “d,” and the data set is the input, where the data set is separately provided from the pipeline. The command identifier refers to the set of instructions that, for each event, performs the operation “value of attribute d=value of attribute a+value of attribute c.”

For example, the pipeline may be a query evaluation pipeline that obtains and processes data from a data store, such as the data store described in FIG. 2 . In such a scenario, the query evaluation pipeline may include a search command, an evaluation command, a statistics command, and/or other commands. By way of another example, the pipeline may be a data processing pipeline, whereby an end user provides a sequence of commands for execution on a user-provided data set. Other pipelines may be processed by the pipeline manager 1800 without departing from the scope of the invention.

Continuing with FIG. 18 , the pipeline interface 1802 is an interface for receiving the pipeline. For example, the pipeline interface 1802 may be a graphical user interface of a web application, a graphical user interface of a local application, an application programming interface, or another interface. For example, the pipeline interface may be all or part of a report generation interface described above. The pipeline interface may encompass or be a part of any other interface described herein.

In one or more embodiments, the pipeline interface 1802 is a text box that is configured to receive a pipeline. Each command in the pipeline may be distinguished from other commands using a delimiter, such as a pipe character, semicolon, colon, tab, or other predefined character. By way of another example, the pipeline interface may be a sequence of text boxes or other input fields for submitting commands. Each user interface widget in the sequence may be configured to receive a command. The order of widgets may define the order of the commands in the sequence.

In one or more embodiments of the invention, commands are executed by command processors 1804. A command processor may be hardware, software, firmware, or any combination thereof. The command processor includes instructions for executing a command when provided with the parameters of the command. In one or more embodiments, each command processor 1804 is specific to the type of command. In other words, the command processor has a one to one correspondence with possible command identifiers that may be in the pipeline. In other embodiments, the command processor may match multiple command identifiers. The command processor is configured to receive a request to execute a command, where the request includes parameters, and execute the instructions of the command processor using the parameters. At least some of the command processors may further use input data that is separately provided from the command in the pipeline, such as from a prior command. The command processor 1804 further includes functionality to return results from executing a command. The command processor may be predefined by the system and distributed with the pipeline manager, created by an information technology specialist, created by a software developer after the pipeline manager is distributed (e.g., as a plug in to the pipeline manager), or by another. Further, although only two command processors are shown, more command processors may exist without departing from the scope of the invention.

Continuing with FIG. 18 , a command execution manager 1806 is configured to parse commands in a pipeline and send the commands to the corresponding command processors. In other words, the command execution manager 1806 includes functionality to issue a call to the corresponding command processor that matches the command identifier of the command in the pipeline, where the call includes the parameters of the command. In one or more embodiments, the command execution manager 1806 is configured to execute commands in order of the pipeline and pass results from one command processor to the next command processor as input data to the next command processor. In one or more embodiments, each subsequent command processor uses the results of the prior command processor. Thus, the command execution manager includes functionality to sequentially execute the pipeline in order and pass the results of the prior command processor, with the parameters to the next command processor. The command execution manager 1806 may be configured to execute multiple pipelines concurrently.

The optimizer 1808 includes functionality to optimize the pipeline using partial semantic information. Semantic information describes the behavior of each command in view of corresponding parameters. For example, the semantics of the operations performed by the command processor may relate the input to the operation with the output of the operation. By way of another example, data semantics may be data types, whether a column or field is modified or not by execution of the command, whether an input variable is used to modify a resulting variable, and other semantic information. Notably, semantic information is distinct from syntax information that relates to form and the structure of each instruction.

Continuing with FIG. 18 , the optimizer 1808 includes functionality to change the parameters of a command, add additional parameters to a command, remove a command, reorder commands, and perform other actions so as to reduce an execution time of the pipeline on a computing system. The optimizer 1808 includes such functionality using incomplete or partial semantic information for at least one command. Incomplete or partial semantic information is semantic information that is missing a semantic value for at least one parameter or function. For example, incomplete semantic information may have missing or partial knowledge of the fields required or referenced by the command, missing of partial knowledge of the fields added, modified or removed by the command, missing or incomplete knowledge of the resulting row cardinality changes introduced by the command, or have other information that is not defined. The incomplete or partial semantic information is indeterminable from the command. In other words, after obtaining partial semantic information for each command of the initial pipeline, the optimizer 1808 is configured to use the partial semantic information in order to construct a revised pipeline that has a reduced execution time as compared to the initial pipeline on the computing system. More specifically, for each missing semantic information, the optimizer includes functionality to determine whether the missing semantic information may be ascertained from other information. If the missing semantic information cannot be obtained, the optimizer includes functionality to determine whether the missing semantic information is required in order to perform an optimization, and, if not required, then to perform the optimization. Examples of optimizations include predicate pushdown and projection elimination.

As discussed above, the system of FIG. 18 may be a query evaluation pipeline. The query evaluation pipeline may be used in the system described above in FIGS. 1-17 . In particular, the system of FIG. 18 may be implemented as at least part of the search head in FIG. 2 . Turning to FIG. 19 , FIG. 19 shows a diagram of the system of FIG. 18 when the pipeline is a query evaluation pipeline implemented in the search head 210 of FIG. 2 . For simplification purposes, the execution manager is not shown in FIG. 19 . The execution manager may perform the same or similar operations as described above with reference to FIG. 18 .

As described above, a query may be divided into phases (i.e., query phases). Each query phase is a command of the query evaluation pipeline. The query phase processor 1906 may be a command processor (described above with respect to FIG. 18 ) for a query phase. For example, a query phase processor 1906 may include a search phase processor that executes a search command to search the data stores and obtain events. In one or more embodiments, the search phase processor may include functionality to invoke the indexers and manage the search to obtain results. The results may be a portion of raw machine data that is associated with a timestamp. A query phase processor 1906 may be an aggregation phase processor. The aggregation phase processor may include functionality to execute an evaluation command. The evaluation command is a request to aggregate data to obtain processed data. For example, if the raw machine data includes connection and disconnection requests by various computer systems to a network device, the aggregation may be the duration of time in which each computer system is connected. A query phase processor 1906 may be a statistics phase processor. The statistics phase processor includes functionality to execute a statistics command. A statistics command is a request to obtain a statistic about data. Although only three query phase processors are shown, other query phase processors may exist without departing from the scope of the invention.

The optimizer 1908 may be the same or similar to the optimizer 1808 described above with reference to FIG. 18 for query evaluation pipelines. In particular, the optimizer 1908 includes functionality to obtain an initial query evaluation pipeline, optimize the query evaluation pipeline to generate a revised query evaluation pipeline.

Query intake 1910 is an application or user interface that includes functionality to receive a query evaluation pipeline. The query intake may be the same or similar to the pipeline interface 1802 described above with reference to FIG. 18 . The query intake 1910 may correspond to all or a portion of the user interfaces discussed above and shown in FIGS. 6A, 6B, and 7A-7D.

FIGS. 20-22 show flowcharts in accordance with one or more embodiments of the invention. While the various steps in these flowcharts are presented and described sequentially, one of ordinary skill will appreciate that some or all of the steps may be executed in different orders, may be combined or omitted, and some or all of the steps may be executed in parallel. Furthermore, the steps may be performed actively or passively. For example, some steps may be performed using polling or be interrupt driven in accordance with one or more embodiments of the invention. By way of an example, determination steps may not require a processor to process an instruction unless an interrupt is received to signify that condition exists in accordance with one or more embodiments of the invention. As another example, determination steps may be performed by performing a test, such as checking a data value to test whether the value is consistent with the tested condition in accordance with one or more embodiments of the invention.

In Block 2002, an initial pipeline including a sequence of commands for execution on a computing system is received. In one or more embodiments, the optimizer receives the initial pipeline from the pipeline interface, such as using a function call to the optimizer. When the optimizer receives the initial pipeline, the initial pipeline may be as a String or a sequence of characters in one or more embodiments. For example, the pipeline may be written in SPL or another language. In one or more embodiments, the initial pipeline may be partitioned into blocks corresponding to commands. The optimizer extracts the commands from the pipeline while maintaining the arguments of the commands.

For query evaluation pipelines, the initial pipeline may be received for performing immediate execution and returning results. In other words, an end user may submit the query evaluation pipeline and expect a report to be generated once based current data in the data store. As another example, the initial pipeline may be received for continual execution and re-execution as new data is received by the data store. Thus, the initial pipeline may be used for monitoring the data store, such as discussed above with reference to section 2.14. In other words, the initial pipeline may be defined the analysis to perform on real data to provide alerts of notable events.

In Block 2004, for each command in the sequence of commands, semantic information is obtained, where the sequence of commands includes a command with incomplete semantic information. In some embodiments, the optimizer includes functionality to obtain semantic information directly. For example, the optimizer may have a set of rules that relates each command and the parameters of the command to the semantic information for the command and parameters. By way of another example, the optimizer may obtain semantic information from another source, such as the corresponding command processors. The semantic information is incomplete for at least one command and may be complete for other commands. Nevertheless, the optimizer continues to optimize the pipeline regardless of only having partial semantic information.

In Block 2006, an AST with the semantic information and a placeholder for the incomplete semantic information is generated. The optimizer builds the AST according to the order of the commands in the pipeline. For example, a command that uses information from a prior command may be closer to the root of the tree than the prior commands in the pipeline. The prior commands may be listed as sources for the command. For each command, the predicates of the command may be listed as parts of the command including the value, type of predicate, and other information. Various techniques may be used to generate an AST and embodiments are not limited to the techniques described. For any semantic information that is missing, a placeholder is added to the AST. The placeholder is a predefined character or sequence of characters that indicates that the semantic information is not available. For example, the placeholder may be a “*”.

In Block 2008, the AST is manipulated to generate a revised AST, where the revised AST corresponds to a revised pipeline that reduces an execution time on the computing system. Because the semantic information is incomplete, the optimizer may first traverse the AST and determine whether any missing semantic information may be determined from the AST. For example, if a first parameter has an unknown data type, but is assigned a value of a second parameter defined in a prior command, and the second parameter has a known data type, then the first parameter is assigned the known data type. Other techniques for determining missing semantic information may be used.

Using the AST, various types of optimization are performed. For each type of optimization, the optimizer makes a determination as to whether missing semantic information is required to perform the optimization. In other words, the optimizer includes functionality to determine whether different values of the semantic information could change the result of executing the pipeline. Determining whether different values could change the pipeline is performed using deduction. For example, if the command is cardinality preserving (i.e. one input row=>one output row) and the command doesn't modify a field that is referenced by a predicate, that predicate may be moved before the command without altering the final results. The reason that the predicate may be moved is because custom commands that related to a search or where command's predicate is commutative with respect to that search or where command. Thus, a pipeline that is “ . . . |custom command|where command| . . . ” may be changed to “ . . . where command|custom command| . . . ”, which should be significantly more efficient as less data is processed.

If missing semantic information is not required, then the optimization is performed.

Different types of optimization may be performed. For example, predicate pushdown is an optimization that applies predicates as early as possible in the pipeline, thereby avoiding searching and loading events that are not applicable. By performing predicate pushdown, the indexers may eliminate or reduce the number of events in the data stores that are searched. Projection elimination reduces amount of each event obtained. In other words, the projection elimination reduces the amount of raw machine data that is returned. Thus, if a portion of raw machine data is not used in subsequent operations of the command pipeline, the projection elimination removes the portion. Notably, the portion may be removed even when the portion has incomplete semantic information based on determining that the portion is not used. By way of another example, a command or a portion of a command may be eliminated when the command or portion of the command is not used. For example, if the command calculates a value that is not used and not returned, the command may be eliminated.

By manipulating the AST by applying various optimizations even when incomplete semantic information exists, one or more embodiments reduce the execution time of the computer system. When multiple pipelines are received and the data being processed is the raw machine data described above that is from various sources, the overall reduction in execution time may be substantial. Further, because developers and user may provide new commands, complete semantic information for the new commands may not be known even by the developer or user. One or more embodiments are able to operate in such an environment to reduce the execution time.

In Block 2010, the revised pipeline is executed. The revised pipeline may be executed by rebuilding the revised pipeline from the revised AST and then performing the execution. The revised pipeline may be executed by extracting commands from the AST and executing each command directly rather than rebuilding the revised AST. Further, executing the revised pipeline may include the optimizer executing the revised pipeline directly, the optimizer issuing a call to the command execution manager to execute the pipeline, or the optimizer performing another function to cause the pipeline to execute. In one or more embodiments, a command of the initial pipeline is not executed. Rather, the system may wait until the revised AST is generated to only execute commands in the revised AST. Thus, actual results of executing a command are not used to perform Block 2008 in one or more embodiments.

FIG. 21 shows a flowchart for a pipeline interface to process a pipeline in accordance with one or more embodiments of the invention. FIG. 21 may be performed prior to FIG. 20 in accordance with one or more embodiments of the invention. In Block 2102, the pipeline interface receives the pipeline in accordance with one or more embodiments of the invention. For example, an end user may submit a data evaluation pipeline via a user interface of a local application or a web application to the pipeline interface.

In Block 2104, a determination is made whether the optimizer is enabled in accordance with one or more embodiments of the invention. The pipeline interface may check a user selectable box that defines whether the optimizer is enabled. Thus, the user may select optimization or not select optimization. If selected, then the optimizer is enabled. If not selected, the optimizer is disabled. In one or more embodiments, the optimizer is preselected as being enabled. Various user interface and/or other application controls may dictate whether the optimizer is enabled. The above technique is only an example.

If the optimizer is disabled, the flow may proceed to Block 2106. In Block 2106, the pipeline interface passes the pipeline to the pipeline execution manager. For example, the pipeline interface may issue a function call to the pipeline execution manager. The function call may include the pipeline as one or more arguments. In Block 2112, the pipeline execution manager executes the pipeline in accordance with one or more embodiments of the invention. For each command in the pipeline according to the order of the pipeline, the pipeline execution manager successively calls the command processor corresponding to the command identifier in the command. The call may directly or indirectly include the parameters of the command and any results from prior execution of the command processor. For example, the parameters and/or results may be passed as arguments of the call or using a shared storage.

Returning to Block 2104, if the optimizer is enabled, the flow may proceed to Block 2110. In Block 2110, the pipeline interface passes the pipeline to the optimizer. For example, the pipeline interface may issue a function call to the optimizer. The function call may include the pipeline as one or more arguments. In Block 2114, the optimizer creates and executes a revised pipeline from the initial pipeline in accordance with one or more embodiments of the invention. Creating and executing the revised pipeline may be performed as discussed above in FIG. 20 . By way of another example, creating and executing the revised pipeline may be performed as presented in FIG. 22 .

In particular, FIG. 22 shows a more detailed flowchart than FIG. 20 for an optimizer to create a revised pipeline and execute the revised pipeline. Some or all of the blocks of FIG. 22 may replace some or all of the blocks of FIG. 20 or may be performed in conjunction with the blocks of FIG. 20 . Further, all embodiments of the invention are not limited to the specific details described in FIG. 22 .

Turning to FIG. 22 , in Block 2202, the initial pipeline is parsed into commands in accordance with one or more embodiments of the invention. In particular, a parser of the optimizer may parse the pipeline into commands by separating out commands according to the predefined delimiter. For each command, the parser may further extract the command identifier and arguments based on predefined character delimiters.

In Block 2204, for each command, the corresponding command processor is invoked with parameters of the command and a request for semantics. Each command processor may include a function that returns semantic information for the corresponding command of the command processor. A function call may be issued that includes the parameters of the command. At this stage, the command is not executed. Further, because a command is not executed, results from a prior command are not used to determine semantic information.

In Block 2206, a set of known semantics are received from each command processor. In response to the function call of Block 2204, the command processor returns the set of known semantics. For at least one command processor, the set of known semantics is incomplete.

In Block 2208, an AST is generated with the set of known commands and an unknown placeholder. The AST may be generated using an AST generator, such as by issuing a call to a JSON AST generator.

In Block 2210, the AST is manipulated to generate a revised AST. Manipulating the AST may be performed as discussed above with reference to Block 2008 of FIG. 20 .

In Block 2212, a revised pipeline of revised commands is generated from the revised AST. The revised AST is traversed to generate the revised pipeline. Each command is ordered and added to the revised pipeline in accordance with the dependencies between the commands. Further, the revised parameters of the commands are added to the revised pipeline.

In Block 2214, in order of pipeline, the corresponding command processor for each revised command is invoked with arguments of revised command and request to execute. In other words, for each command in the revised pipeline according to the order of the revised pipeline, the optimizer successively calls the command processor corresponding to the command identifier in the command. The call may directly or indirectly include the parameters of the command and any results from prior execution of the command processor. For example, the parameters and/or results may be passed as arguments of the call or using a shared storage. Because of the optimizations performed, the amount of execution time to execute the revised pipeline is decreased over the initial pipeline.

The examples shown in FIG. 23A, FIG. 23B, and described below is for explanatory purposes only and not intended to limit the scope of the invention.

FIG. 23A shows an example of a query pipeline in accordance with one or more embodiments of the invention. In particular, the original query (2300) has multiple commands, each command separated from other commands by a pipe symbol (i.e., “I”). The commands include a search command for 500 search results. An evaluation command that, for each search result individually, multiplies fields a and b, then stores the multiplied result into field x of the search result. The evaluation command then divides x by c and puts the result in field y of the search result. The next command is a where command that filters out any search result where a is not greater than 10 and x is not greater than 100. The fields command returns only fields x, a, and b of the search results.

The query intake receives the original query and sends the original query to the optimizer. The optimizer parses the query into phrases (2302), which are comma separated and on separate lines as shown in FIG. 23A. The optimizer then issues separate calls to the query phase processors (2304). For example, the optimizer issues a separate call to the search processor for the search command, to the evaluation processor for the evaluation command, to the where processor for the where command, and to the fields processor for the fields command. In response, each command processor responds with syntax information for the command. Notably, the syntax information does not include information from executing the command, but rather only syntax that can be gathered from the command itself.

The optimizer than builds the following AST using the obtained syntax information. To aid in readability for visual explanatory purposes only, the AST shown below is in an outline tree view. In the optimizer, the parenthesis and other delimiting characters are sufficient to indicate the structure of the tree. As shown in the AST below, any missing information that is not known is marked with a “s” to indicate that the information is not known.

1. {  a. “pipeline”: “streaming”,  b. “keep_column_order”: false,  c. “sources”: [{   i. “pipeline”: “streaming”,   ii. “predicate”: {    1. “args”: [     a. {      i. “args”: [       1. {        a. “type”: “field”,        b. “value”: “a”       2. },       3. {        a. “type”: “number”,        b. “value”: 10       4. }      ii. ],      iii. “type”: “function”,      iv. ’“value”: “>”     b. },     c. {      i. “args”: [       1. {        a. “type”: “field”,        b. “value”: “x”       2. },       3. {        a. “type”: “number”,        b. “value”: 100       4. }      ii. ],      iii. “type”: “function”,      iv. “value”: “>”     d. }    2. ],    3. “type”: “function”,    4. “value”: “AND”   iii. },   iv. “sources”: [{    1. “pipeline”: “streaming”,    2. “assignments”: [     a. {      i. “expression”: “a*b”,      ii. “field”: “x”,      iii. “value”: {       1. “args”:[        a. {         i. “type”: “field”,         ii. “value”: “a”        b. },        c. {         i. “type”: “field”,         ii. “value”: “b”        d. }       2. ],       3. “type”: “function”,       4. “value”: “*”      iv. }     b. },     c. {      i. “expression”: “x/c”,      ii. “field”: “y”,      iii. “value”: {       1. “args”: [        a. {         i. “type”: “field”,         ii. “value”: “x”        b. },        c. {         i. “type”: “field”,         ii. “value”: “c”        d. }       2. ],       3. “type”: “function”,       4. “value”: “/”      iv. }     d. }    3. ],    4. “sources”: [{     a. “pipeline”: “streaming”,     b. “predicate”: {      i. “args”: [{       1. “type”: “term”,       2. “value”: “500”      ii. }],      iii. “type”: “function”,      iv. “value”: “AND”     c. },     d. “fields_and_properties”: [      i. {       1. “referenced”: true,       2. “name”: “_raw”      ii. },      iii. {       1. “name”: “*”,       2. “modified”: true      iv. }     e. ],     f. “type”: “SP_STREAM”,     g. “command”: “search”    5. }],    6. “fields_and_properties”: [     a. {      i. “referenced”: true,      ii. “name”: “a”     b. },     c. {      i. “referenced”: true,      ii. “name”: “b”     d. },     e. {      i. “referenced”: true,      ii. “name”:“c”     f. },     g. {      i. “referenced”: true,      ii. “name”: “x”,      iii. “modified”: true     h. },     i. {      i. “name”: “y”,      ii. “modified”: true     j. }    7. ],    8. “type”: “SP_STREAM”,    9. “command”: “eval”   v. }],   vi. “fields_and_properties”: [    1. {     a. “referenced”: true,     b. “name”: “a”    2. },    3. {     a. “referenced”: true,     b. “name”: “x”    4. }   vii. ],   viii. “type”: “SP_STREAM”,   ix. “command”: “where”  d. }],  e. “keep_underscored”: true,  f. “fields_and_properties”: [   i. {    1. “filterable”: true,    2. “referenced”: true,    3. “name”: “a”   ii. },   iii. {    1. “filterable”: true,    2. “referenced”: true,    3. “name”: “b”   iv. },   v. {    1. “filterable”: true,    2. “referenced”: true,    3. “name”:“x”   vi. },   vii. {    1. “removed”: true,    2. “name”: “*”   viii. },   ix. {    1. “filterable”: true,    2. “name”: “_*”   x. }  g. ],  h. “type”: “SP_STREAM”,  i. “remove_attributes”: false,  j. “field_list”: [   i. “x”,   ii. “a”,   iii. “b”  k. ],  1. “command”: “fields”,  m. “table”: false 2.}

Continuing with the example, based on the analysis of the above AST, the optimizer performs predicate pushdown. To perform predicate pushdown, the optimizer visits nodes (e.g., shown as separate lines) in the AST looking for predicates it can push down. While visiting the nodes, the optimizer finds the where command and notices that the optimizer can push half the where predicate (shown in bold in the AST above) down to the root search (shown in bold in the AST below). In the AST, pushing down mean pushing the nodes as child nodes of other nodes.

1. {  a. “pipeline”: “streaming”,  b. “keep_column_order”: false,  c. “sources”: [{   i. “pipeline”: “streaming”,   ii. “predicate”: {    1. “args”: [{     a. “args”: [      74      i. {       1. “type”: “field”,       2. “value”: “x”      ii. },      iii. {       1. “type”: “number”,       2. “value”: 100      iv. }     b. ],     c. “type”: “function”,     d. “value”: “>”    2. }],    3. “type”: “function”,    4. “value”: “AND”   iii. },   iv. “sources”: [{    1. “pipeline”: “streaming”,    2. “assignments”: [     a. {      i. “expression”: “a*b”,      ii. “field”: “x”,      iii. “value”: {       1. “args”: [        a. {         i. “type”: “field”,         ii. “value”: “a”        b. },        c. {         i. “type”: “field”,         ii. “value”: “b”        d. }       2. ],       3. “type”: “function”,       4. “value”: “*”      iv. }     b. },     c. {      i. “expression”: “x/c”,      ii. “field”: “y”,      iii. “value”: {       1. “args”: [        a. {         i. “type”: “field”,         ii. “value”: “x”        b. },        c. { i. “type”: “field”, ii. “value”: “c”        d. }       2. ],       3. “type”: “function”,       4. “value”: “/”      iv. }     d. }    3. ],    4. “sources”: [{     a. “pipeline”: “streaming”,     b. “predicate”: {      i. “args”: [       1. {        a. “type”: “term”,        b. “value”: “500”       2. },       3. {        a. “args”: [         i. {         ii. “type”: “field”,         iii. “value”: “a”         iv. },         v. {         vi. “type”: “string”,         vii. “value”: “10”         viii. }        b. ],        c. “is_numeric”: false,        d. “type”: “function”,        e. “value”: “>”,        f. “is_indexed”: false       4. }      ii. ],      iii. “type”: “function”,      iv. “value”: “AND”     c. },     d. “fields_and_properties”: [      i. {       1. “referenced”: true,       2. “name”: “a”      ii. },      iii. {       1. “referenced”: true,       2. “name”: “_raw”      iv. },      v. {       1. “name”: “*”,       2. “modified”: true      vi. }     e. ],     f. “type”: “SP_STREAM”,     g. “command”: “search”    5. }],    6. “fields_and_properties”: [     a. {      i. “referenced”: true,      ii. “name”: “a”     b. },     c. {      i. “referenced”: true,      ii. “name”: b     d. },     e. {      i. “referenced”: true,      ii. “name”:“c”     f. },     g. {      i. “referenced”: true,      ii. “name”: “x”,      iii. “modified”: true     h. },     i. {      i. “name”: “y”,      ii. “modified”: true     j. }    7. ],    8. “type”: “SP_STREAM”,    9. “command”: “eval”   v. }],   vi. “fields_and_properties”: [{    1. “referenced”: true,    2. “name”: “x”   vii. }],   viii. “type”: “SP_STREAM”,   ix. “command”: “where”  d. }],  e. “keep_underscored”: true,  f. “fields_and_properties”: [   i. {    1. “filterable”: true,    2. “referenced”: true,    3. “name”: “a”   ii. },   iii. {    1. “filterable”: true,    2. “referenced”: true,    3. “name”: “b”   iv. },   v. {    1. “filterable”: true,    2. “referenced”: true,    3. “name”: “x”   vi. },   vii. {    1. “removed”: true,    2. “name”: “*”   viii. },   ix. {    1. “filterable”: true,    2. “name”:“_*”   x. }  g. ]  h. “type”: “SP_STREAM”,  i. “remove_attributes”: false,  j. “field_list”: [   i. “x”,   ii. “a”,   iii. “b”  k. ],  l. “command”: “fields”,  m. “table”: false 2. }

As a result of the predicate pushdown, the underlying original query has been optimized from:

search 500|eval x=a*b, y=x/c|where a>10 AND x>100|fields x, a, b

to:

search 500 a>10|eval x=a*b, y=x/c|where x>100|fields x, a, b

The predicate pushdown is possible because the evaluation command advertises via the AST that the a field is unmodified by that command, hence a filter before and a filter after are equivalent.

Continuing with the example, the optimizer performs projection elimination by visiting the AST looking for unnecessary calculations. The optimizer identifies the y fields as not being needed. This is shown in that the fields_and_properties for the commands that the fields command does not reference Y. Thus, the projection elimination removes y from the AST as shown below (shown in bold with the comment “//removed section”):

l. {  a. “pipeline”: “streaming”,  b. “keep_column_order”: false,  c. “sources”: [{   i. “pipeline”: “streaming”,   ii. “predicate”: {    1. “args”: [{     a. “args”: [      i. {       1. “type”: “field”,       2. “value”: “x”      ii. },      iii. {       1. “type”: “number”,       2. “value”: 100      iv. }     b. ],     c. “type”: “function”,     d. “value”: “>”    2. }],    3. “type”: “function”,    4. “value”: “AND”   iii. },   iv. “sources”: [{    1. “pipeline”: “streaming”,    2. “assignments”: [     a. {      i. “expression”: “a*b”,      ii. “field”: “x”,      iii. “value”: {       1. “args”: [        a. {         i. “type”: “field”,         ii. “value”: “a”        b. },        c. {         i. “type”: “field”,         ii. “value”: “b”        d. }       2. ],       3. “type”: “function”,       4. “value”: “*”      iv. }     b. }     c. //REMOVED SECTION    3. ],    4. “sources”: [{     a. “pipeline”: “streaming”,     b. “predicate”: {      i. “args”: [       1. {        a. “type”: “term”,        b. “value”: “500”       2. },       3. {        a. “args”: [         i. {         ii. “type”: “field”,         iii. “value”: “a”         iv. },         v. {         vi. “type”: “string”,         vii. “value”: “10”         viii. }        b. ],        c. “is_numeric”: false,        d. “type”: “function”,        e. “value”: “>”,        f. “is_indexed”: false       4. }      ii. ],      iii. “type”: “function”,      iv. “value”: “AND”     c. },     d. “fields_and_properties”: [      i. {       1. “referenced”: true,       2. “name”: “a”      ii. },      iii. {       1. “referenced”: true,       2. “name”: “_raw”      iv. },      v. {       1. “name”: “*”,       2. “modified”: true      vi. }     e. ],     f. “type”: “SP_STREAM”,     g. “command”: “search”    5. }],    6. “fields_and_properties”: [     a. {      i. “referenced”: true,      ii. “name”: “a”     b. },     c. {      i. “referenced”: true,      ii. “name”: “b”     d. },     e. {      i. “referenced”: true,      ii. “name”: “c”     f. },     g. {      i. “referenced”: true,      ii. “name”: “x”,      iii. “modified”: true     h. },     i. {      i. “name”: “y”,      ii. “modified”: true     j. }    7. ],    8. “type”: “SP_STREAM”,    9. “command”: “eval”   v. }],   vi. “fields_and_properties”: [{    1. “referenced”: true,    2. “name”: “x”   vii. }],   viii. “type”: “SP_STREAM”,   ix. “command”: “where”  d. }],  e. “keep_underscored”: true,  f. “fields_and_properties”: [   i. {    1. “filterable”: true,    2. “referenced”: true,    3. “name”: “a”   ii. },   iii. {    1. “filterable”: true,    2. “referenced”: true,    3. “name”: “b”   iv. },   v. {    1. “filterable”: true,    2. “referenced”: true,    3. “name”: “x”   vi. },   vii. {    1. “removed”: true,    2. “name”: “*”   viii. },   ix. {    1. “filterable”: true,    2. “name”: “_*”   x. }  g. ],  h. “type”: “SP_STREAM”,  i. “remove_attributes”: false,  j. “field_list”: [   i. “x”,   ii. “a”,   iii. “b”  k. ],  l. “command”: “fields”,  m. “table”: false 2.}

In the above example, the resulting optimized query is:

search 500 a>10|eval x=a*b|where x>100|fields x, a, b

With the predicate pushdown, the number of search results are greatly reduced, thereby reducing the number of search results that are processed. With the projection elimination, fewer calculations are performed on each returned search result. As shown, even where only partial information is known, the optimizer causes the computing system to operate more efficiently.

In the example of FIG. 23B, consider the scenario in which the commands submitted in the original query (2320) are identical to the commands submitted in 23A with the exception that rather than call a native evaluation command, a custom evaluation command (i.e., “myeval”) is called. As with the example of 23A, the optimizer parses the query into phrases (2322) and calls the corresponding query phrase processor for each phase (2324). The result is the following AST (the bolded section below shows the modification from example 23A).

1. {  a. “pipeline”: “streaming”,  b. “keep_column_order”: false,  c. “sources”: [{   i. “pipeline”: “streaming”,   ii. “predicate”: {    1. “args”: [     a. {      i. “args”: [       1. {        a. “type”: “field”,        b. “value”: “a”       2. },       3. {        a. “type”: “number”,        b. “value”: 10       4. }      ii. ],      iii. “type”: “function”,      iv. “value”: “>”     b. },     c. {      i. “args”: [       l. {        a. “type”: “field”,        b. “value”: “x”       2. },       3. {        a. “type”: “number”,        b. “value”: 100       4. }      ii. ],      iii. “type”: “function”,      iv. “value”: “>”     d. }    2. ],    3. “type”: “function”,    4. “value”: “AND”   iii. },   iv. “sources”: [{    1. “pipeline”: “streaming”,    2. “assignments”: [     a. {      i. “expression”: “a*b”,      ii. “field”: “x”,      iii. “value”: {       1. “args”: [        a. {         i. “type”: “field”,         ii. “value”: “a”        b. },        c. {         i. “type”: “field”,         ii. “value”: “b”        d. }       2. ],       3. “type”: “function”,       4. “value”: “*”      iv. }     b. },     c. {      i. “expression”: “x/c”,      ii. “field”: “y”.      iii. “value”: {       1. “args”: [        a. {         i. “type”: “field”,         ii. “value”: “x”        b. },        c. {         i. “type”: “field”,         ii. “value”: “c”        d. }       2. ],       3. “type”: “function”,       4. “value”: “/”      iv. }     d. }    3. ],    4. “sources”: [{     a. “pipeline”: “streaming”,     b. “predicate”: {      i. “args”: [{       1. “type”: “term”,       2. “value”: “500”      ii. }],      iii. “type”: “function”,      iv. “value”: “AND”     c. },     d. “fields_and_properties”: [      i. {       1. “referenced”: true,       2. “name”: “_raw”      ii. },      iii. {       1. “name”:       2. “modified”: true      iv. }     e. ],     f. “type”: “SP_STREAM”,     g. “command”: “search”    5. }],    6. “fields_and_properties”: [     a. {      i. “modified”: true,      ii. “name”: “X”     b. },     c. {      i. “modified”: true,      ii. “name”: “Y”     d. },     e. {      i. “name”: “*”      ii. “referenced”: true,     f. },    7. ],    8. “type”: “SP_STREAM”,    9. “command”: “myeval”   v. }],   vi. “fields_and_properties”: [    1. {     a. “referenced”: true,     b. “name”: “a”    2. },    3. {     a. “referenced”: true,     b. “name”: “x”    4. }   vii. ],   viii. “type”: “SP_STREAM”,   ix. “command”: “where”  d. }],  e. “keep_underscored”: true,  f. “fields_and_properties”: [    i. {     1. “filterable”: true,     2. “referenced”: true,     3. “name”: “a”    ii. },    iii. {     1. “filterable”: true,     2. “referenced”: true,     3. “name”: “b”    iv. },    v. {     1. “filterable”: true,     2. “referenced”: true,     3. “name”: “x”    vi. },    vii. {     1. “removed”: true,     2. “name”: “*”    viii. },    ix. {     1. “filterable”: true,     2. “name”: “_*”    x. }  g. ],  h. “type”: “SP_STREAM”,  i. “remove_attributes”: false,  j. “field_list”: [    i. “x”,    ii. “a”,    iii. “b”  k. ],  l. “command”: “fields”,  m. “table”: false 2.}

In the example of 23B, the optimizer may perform predicate pushdown for similar reasons as the example of 23A. However, because the custom evaluation command does not identify the fields that are modified, projection elimination cannot be performed. In many cases, the amount of information is dependent on the custom command author's ability to provide semantic information. Nevertheless, even with the incomplete information, the query pipeline can be optimized from:

search 500|myeval x=a*b, y=x/c|where a>10 AND x>100|fields x, a, b

to:

search 500 a>10|myeval x=a*b, y=x/c|where x>100|fields x, a, b

Notably, even though the optimization reduces the number of search results (i.e., to only those search results having a field a greater than 10) processed by the myeval command processor in the above query pipeline, the above optimization is still capable of being performed. Thus, as shown, even with the incomplete semantic information, one or more embodiments reduce the execution time on the computing system.

4.0 Hardware

The various components of the figures may be a computing system or implemented on a computing system. For example, the operations of the data stores, indexers, search heads, host device(s), client devices, data intake and query systems, data sources, external resources, and/or any other component shown and/or described above may be performed by a computing system. A computing system may include any combination of mobile, desktop, server, router, switch, embedded device, or other types of hardware. For example, as shown in FIG. 5.1 , the computing system may include one or more computer processors, non-persistent storage (e.g., volatile memory, such as random access memory (RAM), cache memory), persistent storage (e.g., a hard disk, an optical drive such as a compact disk (CD) drive or digital versatile disk (DVD) drive, a flash memory, etc.), a communication interface (e.g., Bluetooth interface, infrared interface, network interface, optical interface, etc.), and numerous other elements and functionalities. The computer processor(s) may be an integrated circuit for processing instructions. For example, the computer processor(s) may be one or more cores or micro-cores of a processor. The computing system may also include one or more input devices, such as a touchscreen, keyboard, mouse, microphone, touchpad, electronic pen, or any other type of input device.

The computing system may be connected to or be a part of a network. For example, the network may include multiple nodes. Each node may correspond to a computing system, such as the computing system, or a group of nodes combined may correspond to the computing system. By way of an example, embodiments of the invention may be implemented on a node of a distributed system that is connected to other nodes. By way of another example, embodiments of the invention may be implemented on a distributed computing system having multiple nodes, where each portion of the invention may be located on a different node within the distributed computing system. Further, one or more elements of the aforementioned computing system may be located at a remote location and connected to the other elements over a network.

The node may correspond to a blade in a server chassis that is connected to other nodes via a backplane. By way of another example, the node may correspond to a server in a data center. By way of another example, the node may correspond to a computer processor or micro-core of a computer processor with shared memory and/or resources.

The nodes in the network may be configured to provide services for a client device. For example, the nodes may be part of a cloud computing system. The nodes may include functionality to receive requests from the client device and transmit responses to the client device. The client device may be a computing system. Further, the client device may include and/or perform all or a portion of one or more embodiments of the invention.

Software instructions in the form of computer readable program code to perform embodiments of the invention may be stored, in whole or in part, temporarily or permanently, on a non-transitory computer readable medium such as a CD, DVD, storage device, a diskette, a tape, flash memory, physical memory, or any other computer readable storage medium. Specifically, the software instructions may correspond to computer readable program code that, when executed by a processor(s), is configured to perform one or more embodiments of the invention.

While the above figures show various configurations of components, other configurations may be used without departing from the scope of the invention. For example, various components may be combined to create a single component. As another example, the functionality performed by a single component may be performed by two or more components.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims. 

What is claimed is:
 1. A method comprising: receiving, by at least one computing system, a query comprising an initial pipeline comprising a sequence of commands for execution on a computing system, wherein the sequence of commands comprises a search command to search for data in a data store, and a second command that uses the data, wherein the data comprises values for at least one field; prior to executing the search command of the sequence of commands, obtaining, for each command in the sequence of commands and by the computing system, semantic information, wherein the sequence of commands comprises a command with a missing semantic value; generating, by the computing system, an abstract semantic tree (AST) with the semantic information and a placeholder for the missing semantic value, wherein the placeholder is a predefined sequence of at least one character that indicates the missing semantic value is missing; traversing the AST to determine the missing semantic value from the AST; replacing the placeholder in the AST with the missing semantic value; generating, by the computing system and using the missing semantic value, a revised AST from the AST, wherein the revised AST corresponds to a revised pipeline with at least one of the search command and the second command revised; and executing, by the computing system, the revised pipeline.
 2. The method of claim 1, further comprising: parsing the initial pipeline into the sequence of commands.
 3. The method of claim 1, further comprising: invoking, for each command in the sequence of commands and prior to executing the search command, a corresponding command processor with a request for the semantic information; and receiving, for each command in the sequence of commands, semantic information comprising known semantics of the command from the corresponding command processor.
 4. The method of claim 1, wherein executing the revised pipeline comprises: invoking, in order specified by the revised pipeline, a command processor for each corresponding command in the revised pipeline with a request execute the corresponding command.
 5. The method of claim 1, further comprising: receiving, by a pipeline interface, the initial pipeline; determining, by the pipeline interface, that an optimizer is enabled; and passing, by the pipeline interface, the initial pipeline to the optimizer to create the revised pipeline.
 6. The method of claim 1, wherein manipulating the AST comprises: performing projection elimination on the AST to generate the revised AST.
 7. The method of claim 1, wherein generating the revised AST is performed before any command of the initial pipeline is executed.
 8. The method of claim 1, wherein the second command is at least one of an evaluation command and a statistics command.
 9. The method of claim 1, further comprising: distributing a revised query in the revised pipeline to a plurality of indexers to obtain a plurality of events, the revised query further limiting a number of events returned from an original query in the initial pipeline based on an evaluation command in the initial pipeline; executing the evaluation command in the revised pipeline on the plurality of events to obtain at least one result; and executing a statistics command in the revised pipeline to obtain a statistic about the at least one result.
 10. The method of claim 1, further comprising: distributing a revised query in the revised pipeline to a plurality of indexers to obtain a plurality of events, the revised query further limiting a number of events returned from an original query in the initial pipeline based on an evaluation command in the initial pipeline, wherein each event in the plurality of events correspond to a portion of raw machine data associated with a timestamp; executing the evaluation command in the revised pipeline on the plurality of events to obtain at least one result; and executing a statistics command in the revised pipeline to obtain a statistic about the at least one result.
 11. The method of claim 1, wherein execution of the revised pipeline is based on a late-binding schema.
 12. The method of claim 1, further comprising: searching raw machine data using a revised query in the revised pipeline to obtain a plurality of events, the revised query further limiting a number of events returned from an original query in the initial pipeline based on an evaluation command in the initial pipeline.
 13. A system comprising: a computing system for executing a revised pipeline; a computer processor for executing instructions that cause the computer processor to perform operations comprising: receiving a query comprising an initial pipeline comprising a sequence of commands for execution on the computing system, wherein the sequence of commands comprises a search command to search for data in a data store, and a second command that uses the data, wherein the data comprises values for at least one field; prior to executing the search command of the sequence of commands, obtaining, for each command in the sequence of commands and by the computing system, semantic information, wherein the sequence of commands comprises a command with a missing semantic value; generating an abstract semantic tree (AST) with the semantic information and a placeholder for the missing semantic value, wherein the placeholder is a predefined sequence of at least one character that indicates the missing semantic value is missing; traversing the AST to determine the missing semantic value from the AST; replacing the placeholder in the AST with the missing semantic value; generating, using the missing semantic value, a revised AST from the AST, wherein the revised AST corresponds to the revised pipeline with at least one of the search command and the second command revised; and executing the revised pipeline.
 14. The system of claim 13, the operations further comprising: parsing the initial pipeline into the sequence of commands.
 15. The system of claim 13, the operations further comprising: invoking, for each command in the sequence of commands and prior to executing the search command, a corresponding command processor with a request for the semantic information; and receiving, for each command in the sequence of commands, semantic information comprising known semantics of the command from the corresponding command processor.
 16. The system of claim 13, wherein executing the revised pipeline comprises: invoking, in order specified by the revised pipeline, a command processor for each corresponding command in the revised pipeline with a request execute the corresponding command.
 17. The system of claim 13, the operations further comprising: receiving, by a pipeline interface, the initial pipeline; determining, by the pipeline interface, that an optimizer is enabled; and passing, by the pipeline interface, the initial pipeline to the optimizer to create the revised pipeline.
 18. The system of claim 13, the operations further comprising: distributing a revised query in the revised pipeline to a plurality of indexers to obtain a plurality of events, the revised query further limiting a number of events returned from an original query in the initial pipeline based on an evaluation command in the initial pipeline; executing the evaluation command in the revised pipeline on the plurality of events to obtain at least one result; and executing a statistics command in the revised pipeline to obtain a statistic about the at least one result.
 19. A non-transitory computer-readable storage medium storing computer-readable program code which, when executed by one or more processors, cause the one or more processors to perform operations, comprising: receiving a query comprising an initial pipeline comprising a sequence of commands for execution on a computing system, wherein the sequence of commands comprises a search command to search for data in a data store, and a second command that uses the data, wherein the data comprises values for at least one field; prior to executing the search command of the sequence of commands, obtaining, for each command in the sequence of commands and by the computing system, semantic information, wherein the sequence of commands comprises a command with a missing semantic value; generating an abstract semantic tree (AST) with the semantic information and a placeholder for the missing semantic value, wherein the placeholder is a predefined sequence of at least one character that indicates the missing semantic value is missing; traversing the AST to determine the missing semantic value from the AST; replacing the placeholder in the AST with the missing semantic value; generating, using the missing semantic value, a revised AST from the AST, wherein the revised AST corresponds to a revised pipeline with at least one of the search command and the second command revised; and executing the revised pipeline.
 20. The non-transitory computer-readable storage medium of claim 19, the operations further comprising: distributing a revised query in the revised pipeline to a plurality of indexers to obtain a plurality of events, the revised query further limiting a number of events returned from an original query in the initial pipeline based on an evaluation command in the initial pipeline; executing the evaluation command in the revised pipeline on the plurality of events to obtain at least one result; and executing a statistics command in the revised pipeline to obtain a statistic about the at least one result. 